[PATCHv3 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

[PATCHv3 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

[Dmitry Safonov]

print_ip_sym() needs to have a log level parameter to comply with other
parts being printed. Otherwise, half of the expected backtrace would be
printed and other may be missing with some logging level.

The following callee(s) are using now the adjusted log level:
- microblaze/unwind: the same level as headers & userspace unwind.
  Note that pr_debug()'s there are for debugging the unwinder itself.
- nds32/traps: symbol addresses are printed with the same log level
  as backtrace headers.
- lockdep: ip for locking issues is printed with the same log level
  as other part of the warning.
- sched: ip where preemption was disabled is printed as error like
  the rest part of the message.
- ftrace: bug reports are now consistent in the log level being used.

Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vincent Chen <deanbo422@gmail.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/microblaze/kernel/unwind.c | 2 +-
 arch/mips/kernel/traps.c        | 4 ++--
 arch/nds32/kernel/traps.c       | 4 ++--
 arch/riscv/kernel/stacktrace.c  | 2 +-
 include/linux/kallsyms.h        | 4 ++--
 kernel/locking/lockdep.c        | 4 ++--
 kernel/sched/core.c             | 6 ++----
 kernel/trace/ftrace.c           | 8 ++++----
 tools/include/linux/kallsyms.h  | 2 +-
 9 files changed, 17 insertions(+), 19 deletions(-)

diff --git a/arch/microblaze/kernel/unwind.c b/arch/microblaze/kernel/unwind.c
index 34c270cb11fc..4241cdd28ee7 100644
--- a/arch/microblaze/kernel/unwind.c
+++ b/arch/microblaze/kernel/unwind.c
@@ -254,7 +254,7 @@ static void microblaze_unwind_inner(struct task_struct *task,
 					task->comm);
 				break;
 			} else
-				print_ip_sym(pc);
+				print_ip_sym(KERN_INFO, pc);
 		}
 
 		/* Stop when we reach anything not part of the kernel */
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 31968cbd6464..de05503c680c 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -123,7 +123,7 @@ static void show_raw_backtrace(unsigned long reg29)
 			break;
 		}
 		if (__kernel_text_address(addr))
-			print_ip_sym(addr);
+			print_ip_sym(KERN_DEFAULT, addr);
 	}
 	printk("\n");
 }
@@ -153,7 +153,7 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
 	}
 	printk("Call Trace:\n");
 	do {
-		print_ip_sym(pc);
+		print_ip_sym(KERN_DEFAULT, pc);
 		pc = unwind_stack(task, &sp, pc, &ra);
 	} while (pc);
 	pr_cont("\n");
diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index f4d386b52622..40625760a125 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c
@@ -108,7 +108,7 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 			if (__kernel_text_address(ret_addr)) {
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(ret_addr);
+				print_ip_sym(KERN_EMERG, ret_addr);
 			}
 			if (--cnt < 0)
 				break;
@@ -124,7 +124,7 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(ret_addr);
+				print_ip_sym(KERN_EMERG, ret_addr);
 			}
 			if (--cnt < 0)
 				break;
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index 02087fe539c6..eeee844fb93d 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -99,7 +99,7 @@ static void notrace walk_stackframe(struct task_struct *task,
 
 static bool print_trace_address(unsigned long pc, void *arg)
 {
-	print_ip_sym(pc);
+	print_ip_sym(KERN_DEFAULT, pc);
 	return false;
 }
 
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 657a83b943f0..98338dc6b5d2 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -165,9 +165,9 @@ static inline int kallsyms_show_value(void)
 
 #endif /*CONFIG_KALLSYMS*/
 
-static inline void print_ip_sym(unsigned long ip)
+static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 {
-	printk("[<%px>] %pS\n", (void *) ip, (void *) ip);
+	printk("%s[<%px>] %pS\n", loglvl, (void *) ip, (void *) ip);
 }
 
 #endif /*_LINUX_KALLSYMS_H*/
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index ac10db66cc63..079e251fdb4a 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -4399,7 +4399,7 @@ static void print_unlock_imbalance_bug(struct task_struct *curr,
 		curr->comm, task_pid_nr(curr));
 	print_lockdep_cache(lock);
 	pr_cont(") at:\n");
-	print_ip_sym(ip);
+	print_ip_sym(KERN_WARNING, ip);
 	pr_warn("but there are no more locks to release!\n");
 	pr_warn("\nother info that might help us debug this:\n");
 	lockdep_print_held_locks(curr);
@@ -5050,7 +5050,7 @@ static void print_lock_contention_bug(struct task_struct *curr,
 		curr->comm, task_pid_nr(curr));
 	print_lockdep_cache(lock);
 	pr_cont(") at:\n");
-	print_ip_sym(ip);
+	print_ip_sym(KERN_WARNING, ip);
 	pr_warn("but there are no locks held!\n");
 	pr_warn("\nother info that might help us debug this:\n");
 	lockdep_print_held_locks(curr);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 3a61a3b8eaa9..e6ea7c17a362 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3864,8 +3864,7 @@ static noinline void __schedule_bug(struct task_struct *prev)
 	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
 	    && in_atomic_preempt_off()) {
 		pr_err("Preemption disabled at:");
-		print_ip_sym(preempt_disable_ip);
-		pr_cont("\n");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
 	}
 	if (panic_on_warn)
 		panic("scheduling while atomic\n");
@@ -6800,8 +6799,7 @@ void ___might_sleep(const char *file, int line, int preempt_offset)
 	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
 	    && !preempt_count_equals(preempt_offset)) {
 		pr_err("Preemption disabled at:");
-		print_ip_sym(preempt_disable_ip);
-		pr_cont("\n");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
 	}
 	dump_stack();
 	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 041694a1eb74..120b4b7f927c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2031,12 +2031,12 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
 	case -EFAULT:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on modifying ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 		break;
 	case -EINVAL:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace failed to modify ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 		print_ip_ins(" actual:   ", (unsigned char *)ip);
 		pr_cont("\n");
 		if (ftrace_expected) {
@@ -2047,12 +2047,12 @@ void ftrace_bug(int failed, struct dyn_ftrace *rec)
 	case -EPERM:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on writing ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 		break;
 	default:
 		FTRACE_WARN_ON_ONCE(1);
 		pr_info("ftrace faulted on unknown error ");
-		print_ip_sym(ip);
+		print_ip_sym(KERN_INFO, ip);
 	}
 	print_bug_type();
 	if (rec) {
diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index 89ca6fe257cc..efb6c3f5f2a9 100644
--- a/tools/include/linux/kallsyms.h
+++ b/tools/include/linux/kallsyms.h
@@ -20,7 +20,7 @@ static inline const char *kallsyms_lookup(unsigned long addr,
 
 #include <execinfo.h>
 #include <stdlib.h>
-static inline void print_ip_sym(unsigned long ip)
+static inline void print_ip_sym(const char *loglvl, unsigned long ip)
 {
 	char **name;
 
-- 
2.26.0

Re: [PATCHv3 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

[Joe Perches]

On Sat, 2020-04-18 at 21:18 +0100, Dmitry Safonov wrote:
> print_ip_sym() needs to have a log level parameter to comply with other
> parts being printed. Otherwise, half of the expected backtrace would be
> printed and other may be missing with some logging level.

I'd rather create another extension to %ps that also emits
the [<address>] along with the symbol lookup and retire
print_ip_sym altogether.

Something like:
---
 lib/vsprintf.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 7c488a..8fce8f 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -2072,6 +2072,8 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
  * - 'S' For symbolic direct pointers (or function descriptors) with offset
  * - 's' For symbolic direct pointers (or function descriptors) without offset
  * - '[Ss]R' as above with __builtin_extract_return_addr() translation
+ * - '[Ss]B' [<address>] and symbolic direct pointers as above
+ *	     (was used previously used as print_ip_sym)
  * - '[Ff]' %pf and %pF were obsoleted and later removed in favor of
  *	    %ps and %pS. Be careful when re-using these specifiers.
  * - 'B' For backtraced symbolic direct pointers with offset
@@ -2183,6 +2185,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
 	case 'S':
 	case 's':
 		ptr = dereference_symbol_descriptor(ptr);
+		if (fmt[1] == 'B')
+			buf += vsprintf(buf, end, "[<%px>] ", ptr);
 		/* Fallthrough */
 	case 'B':
 		return symbol_string(buf, end, ptr, spec, fmt);

Re: [PATCHv3 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

[Dmitry Safonov]

Hi Joe,

On 4/18/20 9:40 PM, Joe Perches wrote:
> On Sat, 2020-04-18 at 21:18 +0100, Dmitry Safonov wrote:
>> print_ip_sym() needs to have a log level parameter to comply with other
>> parts being printed. Otherwise, half of the expected backtrace would be
>> printed and other may be missing with some logging level.
> 
> I'd rather create another extension to %ps that also emits
> the [<address>] along with the symbol lookup and retire
> print_ip_sym altogether.

Makes sense.
Would you mind if I'll do it on the top of these patches?
[not to mix new printk-format with patches those add loglvl parameter]

> 
> Something like:
> ---
>  lib/vsprintf.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/lib/vsprintf.c b/lib/vsprintf.c
> index 7c488a..8fce8f 100644
> --- a/lib/vsprintf.c
> +++ b/lib/vsprintf.c
> @@ -2072,6 +2072,8 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
>   * - 'S' For symbolic direct pointers (or function descriptors) with offset
>   * - 's' For symbolic direct pointers (or function descriptors) without offset
>   * - '[Ss]R' as above with __builtin_extract_return_addr() translation
> + * - '[Ss]B' [<address>] and symbolic direct pointers as above
> + *	     (was used previously used as print_ip_sym)
>   * - '[Ff]' %pf and %pF were obsoleted and later removed in favor of
>   *	    %ps and %pS. Be careful when re-using these specifiers.
>   * - 'B' For backtraced symbolic direct pointers with offset
> @@ -2183,6 +2185,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
>  	case 'S':
>  	case 's':
>  		ptr = dereference_symbol_descriptor(ptr);
> +		if (fmt[1] == 'B')
> +			buf += vsprintf(buf, end, "[<%px>] ", ptr);
>  		/* Fallthrough */
>  	case 'B':
>  		return symbol_string(buf, end, ptr, spec, fmt);
> 
> 

Thanks,
          Dmitry

Re: [PATCHv3 01/50] kallsyms/printk: Add loglvl to print_ip_sym()

[Joe Perches]

On Mon, 2020-04-20 at 18:25 +0100, Dmitry Safonov wrote:
> Hi Joe,

Hi Dmitry.

> On 4/18/20 9:40 PM, Joe Perches wrote:
> > On Sat, 2020-04-18 at 21:18 +0100, Dmitry Safonov wrote:
> > > print_ip_sym() needs to have a log level parameter to comply with other
> > > parts being printed. Otherwise, half of the expected backtrace would be
> > > printed and other may be missing with some logging level.
> > 
> > I'd rather create another extension to %ps that also emits
> > the [<address>] along with the symbol lookup and retire
> > print_ip_sym altogether.
> 
> Makes sense.
> Would you mind if I'll do it on the top of these patches?
> [not to mix new printk-format with patches those add loglvl parameter]

Of course not, but the proposal below doesn't compile
and I've been playing with a slightly different
implementation.

I'll post it in a few days.

[PATCHv3 02/50] alpha: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: linux-alpha@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/alpha/kernel/traps.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index f6b9664ac504..2402f1777f54 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -121,10 +121,10 @@ dik_show_code(unsigned int *pc)
 }
 
 static void
-dik_show_trace(unsigned long *sp)
+dik_show_trace(unsigned long *sp, const char *loglvl)
 {
 	long i = 0;
-	printk("Trace:\n");
+	printk("%sTrace:\n", loglvl);
 	while (0x1ff8 & (unsigned long) sp) {
 		extern char _stext[], _etext[];
 		unsigned long tmp = *sp;
@@ -133,24 +133,25 @@ dik_show_trace(unsigned long *sp)
 			continue;
 		if (tmp >= (unsigned long) &_etext)
 			continue;
-		printk("[<%lx>] %pSR\n", tmp, (void *)tmp);
+		printk("%s[<%lx>] %pSR\n", loglvl, tmp, (void *)tmp);
 		if (i > 40) {
-			printk(" ...");
+			printk("%s ...", loglvl);
 			break;
 		}
 	}
-	printk("\n");
+	printk("%s\n", loglvl);
 }
 
 static int kstack_depth_to_print = 24;
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+			const char *loglvl)
 {
 	unsigned long *stack;
 	int i;
 
 	/*
-	 * debugging aid: "show_stack(NULL);" prints the
+	 * debugging aid: "show_stack(NULL, NULL, KERN_EMERG);" prints the
 	 * back trace for this cpu.
 	 */
 	if(sp==NULL)
@@ -163,14 +164,19 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 		if ((i % 4) == 0) {
 			if (i)
 				pr_cont("\n");
-			printk("       ");
+			printk("%s       ", loglvl);
 		} else {
 			pr_cont(" ");
 		}
 		pr_cont("%016lx", *stack++);
 	}
 	pr_cont("\n");
-	dik_show_trace(sp);
+	dik_show_trace(sp, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
 
 void
@@ -184,7 +190,7 @@ die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 	printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
 	dik_show_regs(regs, r9_15);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-	dik_show_trace((unsigned long *)(regs+1));
+	dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT);
 	dik_show_code((unsigned int *)regs->pc);
 
 	if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
@@ -625,7 +631,7 @@ do_entUna(void * va, unsigned long opcode, unsigned long reg,
 	printk("gp = %016lx  sp = %p\n", regs->gp, regs+1);
 
 	dik_show_code((unsigned int *)pc);
-	dik_show_trace((unsigned long *)(regs+1));
+	dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT);
 
 	if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
 		printk("die_if_kernel recursion detected.\n");
-- 
2.26.0

[PATCHv3 03/50] arc: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

As a good side-effect header "Stack Trace:" is now printed with the same
log level as the rest of backtrace.

Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-snps-arc@lists.infradead.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arc/include/asm/bug.h     |  3 ++-
 arch/arc/kernel/stacktrace.c   | 21 +++++++++++++++------
 arch/arc/kernel/troubleshoot.c |  2 +-
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/arch/arc/include/asm/bug.h b/arch/arc/include/asm/bug.h
index 0be19fd1a412..4c453ba96c51 100644
--- a/arch/arc/include/asm/bug.h
+++ b/arch/arc/include/asm/bug.h
@@ -13,7 +13,8 @@
 struct task_struct;
 
 void show_regs(struct pt_regs *regs);
-void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs);
+void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
+		     const char *loglvl);
 void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 			    unsigned long address);
 void die(const char *str, struct pt_regs *regs, unsigned long address);
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 1e440bbfa876..24f9cd8a12c9 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -158,9 +158,11 @@ arc_unwind_core(struct task_struct *tsk, struct pt_regs *regs,
 /* Call-back which plugs into unwinding core to dump the stack in
  * case of panic/OOPs/BUG etc
  */
-static int __print_sym(unsigned int address, void *unused)
+static int __print_sym(unsigned int address, void *arg)
 {
-	printk("  %pS\n", (void *)address);
+	const char *loglvl = arg;
+
+	printk("%s  %pS\n", loglvl, (void *)address);
 	return 0;
 }
 
@@ -217,17 +219,24 @@ static int __get_first_nonsched(unsigned int address, void *unused)
  *-------------------------------------------------------------------------
  */
 
-noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs)
+noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
+			      const char *loglvl)
 {
-	pr_info("\nStack Trace:\n");
-	arc_unwind_core(tsk, regs, __print_sym, NULL);
+	printk("%s\nStack Trace:\n", loglvl);
+	arc_unwind_core(tsk, regs, __print_sym, (void *)loglvl);
 }
 EXPORT_SYMBOL(show_stacktrace);
 
 /* Expected by sched Code */
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+			const char *loglvl)
+{
+	show_stacktrace(tsk, NULL, loglvl);
+}
+
 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
-	show_stacktrace(tsk, NULL);
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
 }
 
 /* Another API expected by schedular, shows up in "ps" as Wait Channel
diff --git a/arch/arc/kernel/troubleshoot.c b/arch/arc/kernel/troubleshoot.c
index d2999503fb8a..660681101523 100644
--- a/arch/arc/kernel/troubleshoot.c
+++ b/arch/arc/kernel/troubleshoot.c
@@ -242,5 +242,5 @@ void show_kernel_fault_diag(const char *str, struct pt_regs *regs,
 
 	/* Show stack trace if this Fatality happened in kernel mode */
 	if (!user_mode(regs))
-		show_stacktrace(current, regs);
+		show_stacktrace(current, regs, KERN_DEFAULT);
 }
-- 
2.26.0

[PATCHv3 04/50] arm/asm: Add loglvl to c_backtrace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to c_backtrace() as a preparation for introducing
show_stack_loglvl().

Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: clang-built-linux@googlegroups.com
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm/include/asm/bug.h     |  3 ++-
 arch/arm/include/asm/traps.h   |  3 ++-
 arch/arm/kernel/traps.c        |  9 +++++----
 arch/arm/kernel/unwind.c       |  2 +-
 arch/arm/lib/backtrace-clang.S |  9 +++++++--
 arch/arm/lib/backtrace.S       | 14 ++++++++++----
 6 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/arch/arm/include/asm/bug.h b/arch/arm/include/asm/bug.h
index deef4d0cb3b5..673c7dd75ab9 100644
--- a/arch/arm/include/asm/bug.h
+++ b/arch/arm/include/asm/bug.h
@@ -82,7 +82,8 @@ void hook_ifault_code(int nr, int (*fn)(unsigned long, unsigned int,
 				       struct pt_regs *),
 		     int sig, int code, const char *name);
 
-extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
+extern asmlinkage void c_backtrace(unsigned long fp, int pmode,
+				   const char *loglvl);
 
 struct mm_struct;
 void show_pte(const char *lvl, struct mm_struct *mm, unsigned long addr);
diff --git a/arch/arm/include/asm/traps.h b/arch/arm/include/asm/traps.h
index 172b08ff3760..987fefb0a4db 100644
--- a/arch/arm/include/asm/traps.h
+++ b/arch/arm/include/asm/traps.h
@@ -29,7 +29,8 @@ static inline int __in_irqentry_text(unsigned long ptr)
 }
 
 extern void __init early_trap_init(void *);
-extern void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame);
+extern void dump_backtrace_entry(unsigned long where, unsigned long from,
+				 unsigned long frame, const char *loglvl);
 extern void ptrace_break(struct pt_regs *regs);
 
 extern void *vectors_page;
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 1e70e7227f0f..2030611f22b8 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -62,7 +62,8 @@ __setup("user_debug=", user_debug_setup);
 
 static void dump_mem(const char *, const char *, unsigned long, unsigned long);
 
-void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame)
+void dump_backtrace_entry(unsigned long where, unsigned long from,
+			  unsigned long frame, const char *loglvl)
 {
 	unsigned long end = frame + 4 + sizeof(struct pt_regs);
 
@@ -76,7 +77,7 @@ void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long
 		dump_mem("", "Exception stack", frame + 4, end);
 }
 
-void dump_backtrace_stm(u32 *stack, u32 instruction)
+void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
 {
 	char str[80], *p;
 	unsigned int x;
@@ -238,7 +239,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	pr_cont("\n");
 
 	if (ok)
-		c_backtrace(fp, mode);
+		c_backtrace(fp, mode, NULL);
 }
 #endif
 
@@ -666,7 +667,7 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 		dump_instr("", regs);
 		if (user_mode(regs)) {
 			__show_regs(regs);
-			c_backtrace(frame_pointer(regs), processor_mode(regs));
+			c_backtrace(frame_pointer(regs), processor_mode(regs), NULL);
 		}
 	}
 #endif
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 11a964fd66f4..343cc27b36c4 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -493,7 +493,7 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		urc = unwind_frame(&frame);
 		if (urc < 0)
 			break;
-		dump_backtrace_entry(where, frame.pc, frame.sp - 4);
+		dump_backtrace_entry(where, frame.pc, frame.sp - 4, NULL);
 	}
 }
 
diff --git a/arch/arm/lib/backtrace-clang.S b/arch/arm/lib/backtrace-clang.S
index 2ff375144b55..6174c45f53a5 100644
--- a/arch/arm/lib/backtrace-clang.S
+++ b/arch/arm/lib/backtrace-clang.S
@@ -17,6 +17,7 @@
 #define sv_pc	r6
 #define mask	r7
 #define sv_lr	r8
+#define loglvl	r9
 
 ENTRY(c_backtrace)
 
@@ -99,6 +100,7 @@ ENDPROC(c_backtrace)
 						@ to ensure 8 byte alignment
 		movs	frame, r0		@ if frame pointer is zero
 		beq	no_frame		@ we have no stack frames
+		mov	loglvl, r2
 		tst	r1, #0x10		@ 26 or 32-bit mode?
 		moveq	mask, #0xfc000003
 		movne	mask, #0		@ mask for 32-bit
@@ -167,6 +169,7 @@ finished_setup:
 		mov	r1, sv_lr
 		mov	r2, frame
 		bic	r1, r1, mask		@ mask PC/LR for the mode
+		mov	r3, loglvl
 		bl	dump_backtrace_entry
 
 /*
@@ -183,6 +186,7 @@ finished_setup:
 		ldr	r0, [frame]		@ locals are stored in
 						@ the preceding frame
 		subeq	r0, r0, #4
+		mov	r2, loglvl
 		bleq	dump_backtrace_stm	@ dump saved registers
 
 /*
@@ -196,7 +200,8 @@ finished_setup:
 		bhi	for_each_frame
 
 1006:		adr	r0, .Lbad
-		mov	r1, frame
+		mov	r1, loglvl
+		mov	r2, frame
 		bl	printk
 no_frame:	ldmfd	sp!, {r4 - r9, fp, pc}
 ENDPROC(c_backtrace)
@@ -209,7 +214,7 @@ ENDPROC(c_backtrace)
 		.long   1005b, 1006b
 		.popsection
 
-.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+.Lbad:		.asciz	"%sBacktrace aborted due to bad frame pointer <%p>\n"
 		.align
 .Lopcode:	.word	0xe92d4800 >> 11	@ stmfd sp!, {... fp, lr}
 		.word	0x0b000000		@ bl if these bits are set
diff --git a/arch/arm/lib/backtrace.S b/arch/arm/lib/backtrace.S
index 582925238d65..872f658638d9 100644
--- a/arch/arm/lib/backtrace.S
+++ b/arch/arm/lib/backtrace.S
@@ -18,6 +18,7 @@
 #define sv_pc	r6
 #define mask	r7
 #define offset	r8
+#define loglvl	r9
 
 ENTRY(c_backtrace)
 
@@ -25,9 +26,10 @@ ENTRY(c_backtrace)
 		ret	lr
 ENDPROC(c_backtrace)
 #else
-		stmfd	sp!, {r4 - r8, lr}	@ Save an extra register so we have a location...
+		stmfd	sp!, {r4 - r9, lr}	@ Save an extra register so we have a location...
 		movs	frame, r0		@ if frame pointer is zero
 		beq	no_frame		@ we have no stack frames
+		mov	loglvl, r2
 
 		tst	r1, #0x10		@ 26 or 32-bit mode?
  ARM(		moveq	mask, #0xfc000003	)
@@ -73,6 +75,7 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		ldr	r1, [frame, #-4]	@ get saved lr
 		mov	r2, frame
 		bic	r1, r1, mask		@ mask PC/LR for the mode
+		mov	r3, loglvl
 		bl	dump_backtrace_entry
 
 		ldr	r1, [sv_pc, #-4]	@ if stmfd sp!, {args} exists,
@@ -80,12 +83,14 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		teq	r3, r1, lsr #11
 		ldreq	r0, [frame, #-8]	@ get sp
 		subeq	r0, r0, #4		@ point at the last arg
+		mov	r2, loglvl
 		bleq	dump_backtrace_stm	@ dump saved registers
 
 1004:		ldr	r1, [sv_pc, #0]		@ if stmfd sp!, {..., fp, ip, lr, pc}
 		ldr	r3, .Ldsi		@ instruction exists,
 		teq	r3, r1, lsr #11
 		subeq	r0, frame, #16
+		mov	r2, loglvl
 		bleq	dump_backtrace_stm	@ dump saved registers
 
 		teq	sv_fp, #0		@ zero saved fp means
@@ -96,9 +101,10 @@ for_each_frame:	tst	frame, mask		@ Check for address exceptions
 		bhi	for_each_frame
 
 1006:		adr	r0, .Lbad
-		mov	r1, frame
+		mov	r1, loglvl
+		mov	r2, frame
 		bl	printk
-no_frame:	ldmfd	sp!, {r4 - r8, pc}
+no_frame:	ldmfd	sp!, {r4 - r9, pc}
 ENDPROC(c_backtrace)
 		
 		.pushsection __ex_table,"a"
@@ -109,7 +115,7 @@ ENDPROC(c_backtrace)
 		.long	1004b, 1006b
 		.popsection
 
-.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+.Lbad:		.asciz	"%sBacktrace aborted due to bad frame pointer <%p>\n"
 		.align
 .Ldsi:		.word	0xe92dd800 >> 11	@ stmfd sp!, {... fp, ip, lr, pc}
 		.word	0xe92d0000 >> 11	@ stmfd sp!, {}
-- 
2.26.0

[PATCHv3 05/50] arm: Add loglvl to unwind_backtrace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to unwind_backtrace() as a preparation for
introducing show_stack_loglvl().

As a good side-effect arm_syscall() is now printing errors with the same
log level as the backtrace.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: clang-built-linux@googlegroups.com
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm/include/asm/unwind.h | 3 ++-
 arch/arm/kernel/traps.c       | 6 +++---
 arch/arm/kernel/unwind.c      | 5 +++--
 3 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/arch/arm/include/asm/unwind.h b/arch/arm/include/asm/unwind.h
index 6e282c33126b..0f8a3439902d 100644
--- a/arch/arm/include/asm/unwind.h
+++ b/arch/arm/include/asm/unwind.h
@@ -36,7 +36,8 @@ extern struct unwind_table *unwind_table_add(unsigned long start,
 					     unsigned long text_addr,
 					     unsigned long text_size);
 extern void unwind_table_del(struct unwind_table *tab);
-extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			     const char *loglvl);
 
 #endif	/* !__ASSEMBLY__ */
 
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 2030611f22b8..685e17c2e275 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -204,7 +204,7 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 #ifdef CONFIG_ARM_UNWIND
 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 {
-	unwind_backtrace(regs, tsk);
+	unwind_backtrace(regs, tsk, KERN_DEFAULT);
 }
 #else
 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
@@ -664,10 +664,10 @@ asmlinkage int arm_syscall(int no, struct pt_regs *regs)
 	if (user_debug & UDBG_SYSCALL) {
 		pr_err("[%d] %s: arm syscall %d\n",
 		       task_pid_nr(current), current->comm, no);
-		dump_instr("", regs);
+		dump_instr(KERN_ERR, regs);
 		if (user_mode(regs)) {
 			__show_regs(regs);
-			c_backtrace(frame_pointer(regs), processor_mode(regs), NULL);
+			c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
 		}
 	}
 #endif
diff --git a/arch/arm/kernel/unwind.c b/arch/arm/kernel/unwind.c
index 343cc27b36c4..d2bd0df2318d 100644
--- a/arch/arm/kernel/unwind.c
+++ b/arch/arm/kernel/unwind.c
@@ -455,7 +455,8 @@ int unwind_frame(struct stackframe *frame)
 	return URC_OK;
 }
 
-void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+		      const char *loglvl)
 {
 	struct stackframe frame;
 
@@ -493,7 +494,7 @@ void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		urc = unwind_frame(&frame);
 		if (urc < 0)
 			break;
-		dump_backtrace_entry(where, frame.pc, frame.sp - 4, NULL);
+		dump_backtrace_entry(where, frame.pc, frame.sp - 4, loglvl);
 	}
 }
 
-- 
2.26.0

[PATCHv3 06/50] arm: Add loglvl to dump_backtrace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to dump_backtrace() as a preparation for
introducing show_stack_loglvl().

As a good side-effect __die() now prints not only "Stack:" header with
KERN_EMERG, but the backtrace itself.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: clang-built-linux@googlegroups.com
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm/kernel/traps.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 685e17c2e275..0f09ace18e6c 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -202,17 +202,19 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 }
 
 #ifdef CONFIG_ARM_UNWIND
-static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+				  const char *loglvl)
 {
-	unwind_backtrace(regs, tsk, KERN_DEFAULT);
+	unwind_backtrace(regs, tsk, loglvl);
 }
 #else
-static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl)
 {
 	unsigned int fp, mode;
 	int ok = 1;
 
-	printk("Backtrace: ");
+	printk("%sBacktrace: ", loglvl);
 
 	if (!tsk)
 		tsk = current;
@@ -239,13 +241,13 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	pr_cont("\n");
 
 	if (ok)
-		c_backtrace(fp, mode, NULL);
+		c_backtrace(fp, mode, loglvl);
 }
 #endif
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
-	dump_backtrace(NULL, tsk);
+	dump_backtrace(NULL, tsk, KERN_DEFAULT);
 	barrier();
 }
 
@@ -289,7 +291,7 @@ static int __die(const char *str, int err, struct pt_regs *regs)
 	if (!user_mode(regs) || in_interrupt()) {
 		dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
 			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
-		dump_backtrace(regs, tsk);
+		dump_backtrace(regs, tsk, KERN_EMERG);
 		dump_instr(KERN_EMERG, regs);
 	}
 
-- 
2.26.0

[PATCHv3 07/50] arm: Wire up dump_backtrace_{entry,stm}

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Now that c_backtrace() always emits correct loglvl, use it for printing.

Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: clang-built-linux@googlegroups.com
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm/kernel/traps.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 0f09ace18e6c..e1be6c85327c 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -68,13 +68,15 @@ void dump_backtrace_entry(unsigned long where, unsigned long from,
 	unsigned long end = frame + 4 + sizeof(struct pt_regs);
 
 #ifdef CONFIG_KALLSYMS
-	printk("[<%08lx>] (%ps) from [<%08lx>] (%pS)\n", where, (void *)where, from, (void *)from);
+	printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
+		loglvl, where, (void *)where, from, (void *)from);
 #else
-	printk("Function entered at [<%08lx>] from [<%08lx>]\n", where, from);
+	printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
+		loglvl, where, from);
 #endif
 
 	if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
-		dump_mem("", "Exception stack", frame + 4, end);
+		dump_mem(loglvl, "Exception stack", frame + 4, end);
 }
 
 void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
@@ -89,12 +91,12 @@ void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
 			if (++x == 6) {
 				x = 0;
 				p = str;
-				printk("%s\n", str);
+				printk("%s%s\n", loglvl, str);
 			}
 		}
 	}
 	if (p != str)
-		printk("%s\n", str);
+		printk("%s%s\n", loglvl, str);
 }
 
 #ifndef CONFIG_ARM_UNWIND
-- 
2.26.0

[PATCHv3 08/50] arm: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: clang-built-linux@googlegroups.com
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm/kernel/traps.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index e1be6c85327c..00455b5bbf8a 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -247,12 +247,18 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 }
 #endif
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
-	dump_backtrace(NULL, tsk, KERN_DEFAULT);
+	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #elif defined(CONFIG_PREEMPT_RT)
-- 
2.26.0

[PATCHv3 09/50] arm64: Add loglvl to dump_backtrace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to dump_backtrace() as a preparation for
introducing show_stack_loglvl().

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm64/include/asm/stacktrace.h |  3 ++-
 arch/arm64/kernel/process.c         |  2 +-
 arch/arm64/kernel/traps.c           | 15 ++++++++-------
 3 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
index 4d9b1f48dc39..fdb913cc0bcb 100644
--- a/arch/arm64/include/asm/stacktrace.h
+++ b/arch/arm64/include/asm/stacktrace.h
@@ -64,7 +64,8 @@ struct stackframe {
 extern int unwind_frame(struct task_struct *tsk, struct stackframe *frame);
 extern void walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
 			    int (*fn)(struct stackframe *, void *), void *data);
-extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+extern void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl);
 
 DECLARE_PER_CPU(unsigned long *, irq_stack_ptr);
 
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 56be4cbf771f..360d3c8b9bb4 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -291,7 +291,7 @@ void __show_regs(struct pt_regs *regs)
 void show_regs(struct pt_regs * regs)
 {
 	__show_regs(regs);
-	dump_backtrace(regs, NULL);
+	dump_backtrace(regs, NULL, KERN_DEFAULT);
 }
 
 static void tls_thread_flush(void)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index cf402be5c573..6e777cbd4eb5 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -53,9 +53,9 @@ static const char *handler[]= {
 
 int show_unhandled_signals = 0;
 
-static void dump_backtrace_entry(unsigned long where)
+static void dump_backtrace_entry(unsigned long where, const char *loglvl)
 {
-	printk(" %pS\n", (void *)where);
+	printk("%s %pS\n", loglvl, (void *)where);
 }
 
 static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
@@ -83,7 +83,8 @@ static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
 	printk("%sCode: %s\n", lvl, str);
 }
 
-void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+		    const char *loglvl)
 {
 	struct stackframe frame;
 	int skip = 0;
@@ -115,11 +116,11 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 				thread_saved_pc(tsk));
 	}
 
-	printk("Call trace:\n");
+	printk("%sCall trace:\n", loglvl);
 	do {
 		/* skip until specified stack frame */
 		if (!skip) {
-			dump_backtrace_entry(frame.pc);
+			dump_backtrace_entry(frame.pc, loglvl);
 		} else if (frame.fp == regs->regs[29]) {
 			skip = 0;
 			/*
@@ -129,7 +130,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 			 * at which an exception has taken place, use regs->pc
 			 * instead.
 			 */
-			dump_backtrace_entry(regs->pc);
+			dump_backtrace_entry(regs->pc, loglvl);
 		}
 	} while (!unwind_frame(tsk, &frame));
 
@@ -138,7 +139,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)
 {
-	dump_backtrace(NULL, tsk);
+	dump_backtrace(NULL, tsk, KERN_DEFAULT);
 	barrier();
 }
 
-- 
2.26.0

[PATCHv3 10/50] arm64: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/arm64/kernel/traps.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 6e777cbd4eb5..516e92332fd0 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -137,12 +137,18 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 	put_task_stack(tsk);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
-	dump_backtrace(NULL, tsk, KERN_DEFAULT);
+	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #elif defined(CONFIG_PREEMPT_RT)
-- 
2.26.0

[PATCHv3 11/50] c6x: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Aurelien Jacquiot <jacquiot.aurelien@gmail.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: linux-c6x-dev@linux-c6x.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/c6x/kernel/traps.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/arch/c6x/kernel/traps.c b/arch/c6x/kernel/traps.c
index ec61034fdf56..4afbf48f1ce0 100644
--- a/arch/c6x/kernel/traps.c
+++ b/arch/c6x/kernel/traps.c
@@ -344,12 +344,13 @@ asmlinkage int process_exception(struct pt_regs *regs)
 
 static int kstack_depth_to_print = 48;
 
-static void show_trace(unsigned long *stack, unsigned long *endstack)
+static void show_trace(unsigned long *stack, unsigned long *endstack,
+		       const char *loglvl)
 {
 	unsigned long addr;
 	int i;
 
-	pr_debug("Call trace:");
+	printk("%sCall trace:", loglvl);
 	i = 0;
 	while (stack + 1 <= endstack) {
 		addr = *stack++;
@@ -364,16 +365,17 @@ static void show_trace(unsigned long *stack, unsigned long *endstack)
 		if (__kernel_text_address(addr)) {
 #ifndef CONFIG_KALLSYMS
 			if (i % 5 == 0)
-				pr_debug("\n	    ");
+				printk("%s\n	    ", loglvl);
 #endif
-			pr_debug(" [<%08lx>] %pS\n", addr, (void *)addr);
+			printk("%s [<%08lx>] %pS\n", loglvl, addr, (void *)addr);
 			i++;
 		}
 	}
-	pr_debug("\n");
+	printk("%s\n", loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
 {
 	unsigned long *p, *endstack;
 	int i;
@@ -398,7 +400,12 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		pr_cont(" %08lx", *p++);
 	}
 	pr_cont("\n");
-	show_trace(stack, endstack);
+	show_trace(stack, endstack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_DEBUG);
 }
 
 int is_valid_bugaddr(unsigned long addr)
-- 
2.26.0

Re: [PATCHv3 11/50] c6x: Add show_stack_loglvl()

[Joe Perches]

On Sat, 2020-04-18 at 21:19 +0100, Dmitry Safonov wrote:
> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with
> lower log level or higher than the stacktrace (depending on
> a platform or user).
[]
> diff --git a/arch/c6x/kernel/traps.c b/arch/c6x/kernel/traps.c
[]
> @@ -344,12 +344,13 @@ asmlinkage int process_exception(struct pt_regs *regs)
>  
>  static int kstack_depth_to_print = 48;
>  
> -static void show_trace(unsigned long *stack, unsigned long *endstack)
> +static void show_trace(unsigned long *stack, unsigned long *endstack,
> +		       const char *loglvl)
>  {
>  	unsigned long addr;
>  	int i;
> 
> -	pr_debug("Call trace:");
> +	printk("%sCall trace:", loglvl);

These are not equivalent transforms as pr_debug
is compiled to nothing unless DEBUG is defined
or CONFIG_DYNAMIC_DEBUG is enabled.

Perhaps all the conversions should be checked
for these "not the same" object code changes.

Re: [PATCHv3 11/50] c6x: Add show_stack_loglvl()

[Tetsuo Handa]

On 2020/04/26 3:18, Joe Perches wrote:
> On Sat, 2020-04-18 at 21:19 +0100, Dmitry Safonov wrote:
>> Currently, the log-level of show_stack() depends on a platform
>> realization. It creates situations where the headers are printed with
>> lower log level or higher than the stacktrace (depending on
>> a platform or user).
> []
>> diff --git a/arch/c6x/kernel/traps.c b/arch/c6x/kernel/traps.c
> []
>> @@ -344,12 +344,13 @@ asmlinkage int process_exception(struct pt_regs *regs)
>>  
>>  static int kstack_depth_to_print = 48;
>>  
>> -static void show_trace(unsigned long *stack, unsigned long *endstack)
>> +static void show_trace(unsigned long *stack, unsigned long *endstack,
>> +		       const char *loglvl)
>>  {
>>  	unsigned long addr;
>>  	int i;
>>
>> -	pr_debug("Call trace:");
>> +	printk("%sCall trace:", loglvl);
> 
> These are not equivalent transforms as pr_debug
> is compiled to nothing unless DEBUG is defined
> or CONFIG_DYNAMIC_DEBUG is enabled.

I guess this user is expecting pr_debug() as unconditional printk(KERN_DEBUG), for
show_trace() and show_stack() will become waste of code if pr_debug() prints nothing.
If this user wants pr_debug() to be conditional, #ifdef'ing these functions is the better.

> 
> Perhaps all the conversions should be checked
> for these "not the same" object code changes.
> 

Re: [PATCHv3 11/50] c6x: Add show_stack_loglvl()

[Dmitry Safonov]

On 4/26/20 2:06 AM, Tetsuo Handa wrote:
> On 2020/04/26 3:18, Joe Perches wrote:
>> On Sat, 2020-04-18 at 21:19 +0100, Dmitry Safonov wrote:
>>> Currently, the log-level of show_stack() depends on a platform
>>> realization. It creates situations where the headers are printed with
>>> lower log level or higher than the stacktrace (depending on
>>> a platform or user).
>> []
>>> diff --git a/arch/c6x/kernel/traps.c b/arch/c6x/kernel/traps.c
>> []
>>> @@ -344,12 +344,13 @@ asmlinkage int process_exception(struct pt_regs *regs)
>>>  
>>>  static int kstack_depth_to_print = 48;
>>>  
>>> -static void show_trace(unsigned long *stack, unsigned long *endstack)
>>> +static void show_trace(unsigned long *stack, unsigned long *endstack,
>>> +		       const char *loglvl)
>>>  {
>>>  	unsigned long addr;
>>>  	int i;
>>>
>>> -	pr_debug("Call trace:");
>>> +	printk("%sCall trace:", loglvl);
>>
>> These are not equivalent transforms as pr_debug
>> is compiled to nothing unless DEBUG is defined
>> or CONFIG_DYNAMIC_DEBUG is enabled.
> 
> I guess this user is expecting pr_debug() as unconditional printk(KERN_DEBUG), for
> show_trace() and show_stack() will become waste of code if pr_debug() prints nothing.
> If this user wants pr_debug() to be conditional, #ifdef'ing these functions is the better.

Agree.

>> Perhaps all the conversions should be checked
>> for these "not the same" object code changes.

I've checked other architectures - it seems only c6x was printing
backtraces with pr_debug().

Is there a user for hiding all backtraces?
If there is, I think it's better to ifdef-out show_stack() under a new
config HIDE_BACKTRACES or something.

Thanks,
          Dmitry

[PATCHv3 12/50] csky: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Guo Ren <guoren@kernel.org>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/csky/kernel/dumpstack.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c
index d67f9777cfd9..c500837390d3 100644
--- a/arch/csky/kernel/dumpstack.c
+++ b/arch/csky/kernel/dumpstack.c
@@ -5,7 +5,7 @@
 
 int kstack_depth_to_print = 48;
 
-void show_trace(unsigned long *stack)
+static void show_trace(unsigned long *stack, const char *loglvl)
 {
 	unsigned long *stack_end;
 	unsigned long *stack_start;
@@ -17,7 +17,7 @@ void show_trace(unsigned long *stack)
 	stack_end = (unsigned long *) (addr + THREAD_SIZE);
 
 	fp = stack;
-	pr_info("\nCall Trace:");
+	printk("%s\nCall Trace:", loglvl);
 
 	while (fp > stack_start && fp < stack_end) {
 #ifdef CONFIG_STACKTRACE
@@ -32,7 +32,8 @@ void show_trace(unsigned long *stack)
 	pr_cont("\n");
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
 {
 	if (!stack) {
 		if (task)
@@ -45,5 +46,10 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 #endif
 	}
 
-	show_trace(stack);
+	show_trace(stack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_INFO);
 }
-- 
2.26.0

Re: [PATCHv3 12/50] csky: Add show_stack_loglvl()

[Andrew Morton]

On Sat, 18 Apr 2020 21:19:06 +0100 Dmitry Safonov <dima@arista.com> wrote:

> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with
> lower log level or higher than the stacktrace (depending on
> a platform or user).
> 
> Furthermore, it forces the logic decision from user to an architecture
> side. In result, some users as sysrq/kdb/etc are doing tricks with
> temporary rising console_loglevel while printing their messages.
> And in result it not only may print unwanted messages from other CPUs,
> but also omit printing at all in the unlucky case where the printk()
> was deferred.
> 
> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
> an easier approach than introducing more printk buffers.
> Also, it will consolidate printings with headers.
> 
> Introduce show_stack_loglvl(), that eventually will substitute
> show_stack().

The csky code has changed a lot in linux-next due to 18c07d23da5a
("csky: Fixup calltrace panic").  I redid this patch as below.  Can we
please review and test?


From: Dmitry Safonov <dima@arista.com>
Subject: csky: add show_stack_loglvl()

Currently, the log-level of show_stack() depends on a platform
realization.  It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).

Furthermore, it forces the logic decision from user to an architecture
side.  In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.  And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers.  Also, it will consolidate
printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u

Link: http://lkml.kernel.org/r/20200418201944.482088-13-dima@arista.com
Signed-off-by: Dmitry Safonov <dima@arista.com>
Cc: Guo Ren <guoren@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/csky/kernel/stacktrace.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

--- a/arch/csky/kernel/stacktrace.c~csky-add-show_stack_loglvl
+++ a/arch/csky/kernel/stacktrace.c
@@ -91,14 +91,21 @@ static void notrace walk_stackframe(stru
 
 static bool print_trace_address(unsigned long pc, void *arg)
 {
-	print_ip_sym(pc);
+	print_ip_sym((const char *)arg, pc);
 	return false;
 }
 
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
+{
+	pr_cont("Call Trace:\n");
+	walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
+}
+
 void show_stack(struct task_struct *task, unsigned long *sp)
 {
 	pr_cont("Call Trace:\n");
-	walk_stackframe(task, NULL, print_trace_address, NULL);
+	walk_stackframe(task, NULL, print_trace_address, KERN_INFO);
 }
 
 static bool save_wchan(unsigned long pc, void *arg)
_

Re: [PATCHv3 12/50] csky: Add show_stack_loglvl()

[Dmitry Safonov]

Hi Andrew,

On 5/15/20 8:23 PM, Andrew Morton wrote:
> On Sat, 18 Apr 2020 21:19:06 +0100 Dmitry Safonov <dima@arista.com> wrote:
> 
>> Currently, the log-level of show_stack() depends on a platform
>> realization. It creates situations where the headers are printed with
>> lower log level or higher than the stacktrace (depending on
>> a platform or user).
>>
>> Furthermore, it forces the logic decision from user to an architecture
>> side. In result, some users as sysrq/kdb/etc are doing tricks with
>> temporary rising console_loglevel while printing their messages.
>> And in result it not only may print unwanted messages from other CPUs,
>> but also omit printing at all in the unlucky case where the printk()
>> was deferred.
>>
>> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
>> an easier approach than introducing more printk buffers.
>> Also, it will consolidate printings with headers.
>>
>> Introduce show_stack_loglvl(), that eventually will substitute
>> show_stack().
> 
> The csky code has changed a lot in linux-next due to 18c07d23da5a
> ("csky: Fixup calltrace panic").  I redid this patch as below.  Can we
> please review and test?

The result looks good to me, thanks for the rebase!

Thanks,
          Dmitry

[PATCHv3 13/50] h8300: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/h8300/kernel/traps.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c
index e47a9e0dc278..6362446563d6 100644
--- a/arch/h8300/kernel/traps.c
+++ b/arch/h8300/kernel/traps.c
@@ -115,7 +115,8 @@ void die(const char *str, struct pt_regs *fp, unsigned long err)
 
 static int kstack_depth_to_print = 24;
 
-void show_stack(struct task_struct *task, unsigned long *esp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
+		       const char *loglvl)
 {
 	unsigned long *stack,  addr;
 	int i;
@@ -125,17 +126,17 @@ void show_stack(struct task_struct *task, unsigned long *esp)
 
 	stack = esp;
 
-	pr_info("Stack from %08lx:", (unsigned long)stack);
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (((unsigned long)stack & (THREAD_SIZE - 1)) >=
 		    THREAD_SIZE-4)
 			break;
 		if (i % 8 == 0)
-			pr_info(" ");
+			printk("%s ", loglvl);
 		pr_cont(" %08lx", *stack++);
 	}
 
-	pr_info("\nCall Trace:\n");
+	printk("%s\nCall Trace:\n", loglvl);
 	i = 0;
 	stack = esp;
 	while (((unsigned long)stack & (THREAD_SIZE - 1)) < THREAD_SIZE-4) {
@@ -150,10 +151,15 @@ void show_stack(struct task_struct *task, unsigned long *esp)
 		 */
 		if (check_kernel_text(addr)) {
 			if (i % 4 == 0)
-				pr_info("       ");
+				printk("%s       ", loglvl);
 			pr_cont(" [<%08lx>]", addr);
 			i++;
 		}
 	}
-	pr_info("\n");
+	printk("%s\n", loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *esp)
+{
+	show_stack_loglvl(task, esp, KERN_INFO);
 }
-- 
2.26.0

[PATCHv3 14/50] hexagon: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

As a good side-effect die() now prints the stacktrace with KERN_EMERG
aligned with other messages.

Cc: Brian Cain <bcain@codeaurora.org>
Cc: linux-hexagon@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Acked-by: Brian Cain <bcain@codeaurora.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/hexagon/kernel/traps.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index 69c623b14ddd..a8a3a210d781 100644
--- a/arch/hexagon/kernel/traps.c
+++ b/arch/hexagon/kernel/traps.c
@@ -79,7 +79,7 @@ static const char *ex_name(int ex)
 }
 
 static void do_show_stack(struct task_struct *task, unsigned long *fp,
-			  unsigned long ip)
+			  unsigned long ip, const char *loglvl)
 {
 	int kstack_depth_to_print = 24;
 	unsigned long offset, size;
@@ -93,9 +93,8 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	if (task == NULL)
 		task = current;
 
-	printk(KERN_INFO "CPU#%d, %s/%d, Call Trace:\n",
-	       raw_smp_processor_id(), task->comm,
-	       task_pid_nr(task));
+	printk("%sCPU#%d, %s/%d, Call Trace:\n", loglvl, raw_smp_processor_id(),
+		task->comm, task_pid_nr(task));
 
 	if (fp == NULL) {
 		if (task == current) {
@@ -108,7 +107,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	}
 
 	if ((((unsigned long) fp) & 0x3) || ((unsigned long) fp < 0x1000)) {
-		printk(KERN_INFO "-- Corrupt frame pointer %p\n", fp);
+		printk("%s-- Corrupt frame pointer %p\n", loglvl, fp);
 		return;
 	}
 
@@ -125,8 +124,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 
 		name = kallsyms_lookup(ip, &size, &offset, &modname, tmpstr);
 
-		printk(KERN_INFO "[%p] 0x%lx: %s + 0x%lx", fp, ip, name,
-			offset);
+		printk("%s[%p] 0x%lx: %s + 0x%lx", loglvl, fp, ip, name, offset);
 		if (((unsigned long) fp < low) || (high < (unsigned long) fp))
 			printk(KERN_CONT " (FP out of bounds!)");
 		if (modname)
@@ -136,8 +134,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 		newfp = (unsigned long *) *fp;
 
 		if (((unsigned long) newfp) & 0x3) {
-			printk(KERN_INFO "-- Corrupt frame pointer %p\n",
-				newfp);
+			printk("%s-- Corrupt frame pointer %p\n", loglvl, newfp);
 			break;
 		}
 
@@ -147,7 +144,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 						+ 8);
 
 			if (regs->syscall_nr != -1) {
-				printk(KERN_INFO "-- trap0 -- syscall_nr: %ld",
+				printk("%s-- trap0 -- syscall_nr: %ld", loglvl,
 					regs->syscall_nr);
 				printk(KERN_CONT "  psp: %lx  elr: %lx\n",
 					 pt_psp(regs), pt_elr(regs));
@@ -155,7 +152,7 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 			} else {
 				/* really want to see more ... */
 				kstack_depth_to_print += 6;
-				printk(KERN_INFO "-- %s (0x%lx)  badva: %lx\n",
+				printk("%s-- %s (0x%lx)  badva: %lx\n", loglvl,
 					ex_name(pt_cause(regs)), pt_cause(regs),
 					pt_badva(regs));
 			}
@@ -178,10 +175,16 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	}
 }
 
-void show_stack(struct task_struct *task, unsigned long *fp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *fp,
+		       const char *loglvl)
 {
 	/* Saved link reg is one word above FP */
-	do_show_stack(task, fp, 0);
+	do_show_stack(task, fp, 0, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *fp)
+{
+	show_stack_loglvl(task, fp, 0, KERN_INFO);
 }
 
 int die(const char *str, struct pt_regs *regs, long err)
@@ -207,7 +210,7 @@ int die(const char *str, struct pt_regs *regs, long err)
 
 	print_modules();
 	show_regs(regs);
-	do_show_stack(current, &regs->r30, pt_elr(regs));
+	do_show_stack(current, &regs->r30, pt_elr(regs), KERN_EMERG);
 
 	bust_spinlocks(0);
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-- 
2.26.0

[PATCHv3 15/50] ia64: Pass log level as arg into ia64_do_show_stack()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to ia64_do_show_stack() as a preparation to
introduce show_stack_loglvl().
Also, make ia64_do_show_stack() static as it's not used outside.

Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/ia64/include/asm/ptrace.h |  1 -
 arch/ia64/kernel/process.c     | 13 +++++++------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/ia64/include/asm/ptrace.h b/arch/ia64/include/asm/ptrace.h
index 7ff574d56429..b3aa46090101 100644
--- a/arch/ia64/include/asm/ptrace.h
+++ b/arch/ia64/include/asm/ptrace.h
@@ -114,7 +114,6 @@ static inline long regs_return_value(struct pt_regs *regs)
   struct task_struct;			/* forward decl */
   struct unw_frame_info;		/* forward decl */
 
-  extern void ia64_do_show_stack (struct unw_frame_info *, void *);
   extern unsigned long ia64_get_user_rbs_end (struct task_struct *, struct pt_regs *,
 					      unsigned long *);
   extern long ia64_peek (struct task_struct *, struct switch_stack *, unsigned long,
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 10cb9382ab76..332c6dfe7333 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -64,12 +64,13 @@ EXPORT_SYMBOL(boot_option_idle_override);
 void (*pm_power_off) (void);
 EXPORT_SYMBOL(pm_power_off);
 
-void
+static void
 ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 {
 	unsigned long ip, sp, bsp;
+	const char *loglvl = arg;
 
-	printk("\nCall Trace:\n");
+	printk("%s\nCall Trace:\n", loglvl);
 	do {
 		unw_get_ip(info, &ip);
 		if (ip == 0)
@@ -77,9 +78,9 @@ ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 
 		unw_get_sp(info, &sp);
 		unw_get_bsp(info, &bsp);
-		printk(" [<%016lx>] %pS\n"
+		printk("%s [<%016lx>] %pS\n"
 			 "                                sp=%016lx bsp=%016lx\n",
-			 ip, (void *)ip, sp, bsp);
+			 loglvl, ip, (void *)ip, sp, bsp);
 	} while (unw_unwind(info) >= 0);
 }
 
@@ -87,12 +88,12 @@ void
 show_stack (struct task_struct *task, unsigned long *sp)
 {
 	if (!task)
-		unw_init_running(ia64_do_show_stack, NULL);
+		unw_init_running(ia64_do_show_stack, (void *)KERN_DEFAULT);
 	else {
 		struct unw_frame_info info;
 
 		unw_init_from_blocked_task(&info, task);
-		ia64_do_show_stack(&info, NULL);
+		ia64_do_show_stack(&info, (void *)KERN_DEFAULT);
 	}
 }
 
-- 
2.26.0

[PATCHv3 16/50] ia64: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-ia64@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/ia64/kernel/process.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 332c6dfe7333..913d9a01cbf9 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -85,18 +85,25 @@ ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 }
 
 void
-show_stack (struct task_struct *task, unsigned long *sp)
+show_stack_loglvl (struct task_struct *task, unsigned long *sp,
+		   const char *loglvl)
 {
 	if (!task)
-		unw_init_running(ia64_do_show_stack, (void *)KERN_DEFAULT);
+		unw_init_running(ia64_do_show_stack, (void *)loglvl);
 	else {
 		struct unw_frame_info info;
 
 		unw_init_from_blocked_task(&info, task);
-		ia64_do_show_stack(&info, (void *)KERN_DEFAULT);
+		ia64_do_show_stack(&info, (void *)loglvl);
 	}
 }
 
+void
+show_stack (struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
+}
+
 void
 show_regs (struct pt_regs *regs)
 {
-- 
2.26.0

[PATCHv3 17/50] m68k: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/m68k/kernel/traps.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index 344f93d36a9a..ffcc5ec4fac3 100644
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -811,13 +811,13 @@ asmlinkage void buserr_c(struct frame *fp)
 
 static int kstack_depth_to_print = 48;
 
-void show_trace(unsigned long *stack)
+static void show_trace(unsigned long *stack, const char *loglvl)
 {
 	unsigned long *endstack;
 	unsigned long addr;
 	int i;
 
-	pr_info("Call Trace:");
+	printk("%sCall Trace:", loglvl);
 	addr = (unsigned long)stack + THREAD_SIZE - 1;
 	endstack = (unsigned long *)(addr & -THREAD_SIZE);
 	i = 0;
@@ -935,7 +935,8 @@ void show_registers(struct pt_regs *regs)
 	pr_cont("\n");
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long *p;
 	unsigned long *endstack;
@@ -949,7 +950,7 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	}
 	endstack = (unsigned long *)(((unsigned long)stack + THREAD_SIZE - 1) & -THREAD_SIZE);
 
-	pr_info("Stack from %08lx:", (unsigned long)stack);
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
 	p = stack;
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (p + 1 > endstack)
@@ -959,7 +960,12 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		pr_cont(" %08lx", *p++);
 	}
 	pr_cont("\n");
-	show_trace(stack);
+	show_trace(stack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_INFO);
 }
 
 /*
-- 
2.26.0

[PATCHv3 18/50] microblaze: Add loglvl to microblaze_unwind_inner()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to microblaze_unwind_inner() as a preparation for
introducing show_stack_loglvl().

Cc: Michal Simek <monstr@monstr.eu>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/microblaze/kernel/unwind.c | 38 ++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/arch/microblaze/kernel/unwind.c b/arch/microblaze/kernel/unwind.c
index 4241cdd28ee7..804bf0c99d8b 100644
--- a/arch/microblaze/kernel/unwind.c
+++ b/arch/microblaze/kernel/unwind.c
@@ -154,7 +154,8 @@ static int lookup_prev_stack_frame(unsigned long fp, unsigned long pc,
 static void microblaze_unwind_inner(struct task_struct *task,
 				    unsigned long pc, unsigned long fp,
 				    unsigned long leaf_return,
-				    struct stack_trace *trace);
+				    struct stack_trace *trace,
+				    const char *loglvl);
 
 /**
  * unwind_trap - Unwind through a system trap, that stored previous state
@@ -162,16 +163,18 @@ static void microblaze_unwind_inner(struct task_struct *task,
  */
 #ifdef CONFIG_MMU
 static inline void unwind_trap(struct task_struct *task, unsigned long pc,
-				unsigned long fp, struct stack_trace *trace)
+				unsigned long fp, struct stack_trace *trace,
+				const char *loglvl)
 {
 	/* To be implemented */
 }
 #else
 static inline void unwind_trap(struct task_struct *task, unsigned long pc,
-				unsigned long fp, struct stack_trace *trace)
+				unsigned long fp, struct stack_trace *trace,
+				const char *loglvl)
 {
 	const struct pt_regs *regs = (const struct pt_regs *) fp;
-	microblaze_unwind_inner(task, regs->pc, regs->r1, regs->r15, trace);
+	microblaze_unwind_inner(task, regs->pc, regs->r1, regs->r15, trace, loglvl);
 }
 #endif
 
@@ -184,11 +187,13 @@ static inline void unwind_trap(struct task_struct *task, unsigned long pc,
  *				  the caller's return address.
  * @trace : Where to store stack backtrace (PC values).
  *	    NULL == print backtrace to kernel log
+ * @loglvl : Used for printk log level if (trace == NULL).
  */
 static void microblaze_unwind_inner(struct task_struct *task,
 			     unsigned long pc, unsigned long fp,
 			     unsigned long leaf_return,
-			     struct stack_trace *trace)
+			     struct stack_trace *trace,
+			     const char *loglvl)
 {
 	int ofs = 0;
 
@@ -214,11 +219,11 @@ static void microblaze_unwind_inner(struct task_struct *task,
 			const struct pt_regs *regs =
 				(const struct pt_regs *) fp;
 #endif
-			pr_info("HW EXCEPTION\n");
+			printk("%sHW EXCEPTION\n", loglvl);
 #ifndef CONFIG_MMU
 			microblaze_unwind_inner(task, regs->r17 - 4,
 						fp + EX_HANDLER_STACK_SIZ,
-						regs->r15, trace);
+						regs->r15, trace, loglvl);
 #endif
 			return;
 		}
@@ -228,8 +233,8 @@ static void microblaze_unwind_inner(struct task_struct *task,
 			if ((return_to >= handler->start_addr)
 			    && (return_to <= handler->end_addr)) {
 				if (!trace)
-					pr_info("%s\n", handler->trap_name);
-				unwind_trap(task, pc, fp, trace);
+					printk("%s%s\n", loglvl, handler->trap_name);
+				unwind_trap(task, pc, fp, trace, loglvl);
 				return;
 			}
 		}
@@ -248,13 +253,13 @@ static void microblaze_unwind_inner(struct task_struct *task,
 		} else {
 			/* Have we reached userland? */
 			if (unlikely(pc == task_pt_regs(task)->pc)) {
-				pr_info("[<%p>] PID %lu [%s]\n",
-					(void *) pc,
+				printk("%s[<%p>] PID %lu [%s]\n",
+					loglvl, (void *) pc,
 					(unsigned long) task->pid,
 					task->comm);
 				break;
 			} else
-				print_ip_sym(KERN_INFO, pc);
+				print_ip_sym(loglvl, pc);
 		}
 
 		/* Stop when we reach anything not part of the kernel */
@@ -285,11 +290,13 @@ static void microblaze_unwind_inner(struct task_struct *task,
  */
 void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
 {
+	const char *loglvl = KERN_INFO;
+
 	if (task) {
 		if (task == current) {
 			const struct pt_regs *regs = task_pt_regs(task);
 			microblaze_unwind_inner(task, regs->pc, regs->r1,
-						regs->r15, trace);
+						regs->r15, trace, loglvl);
 		} else {
 			struct thread_info *thread_info =
 				(struct thread_info *)(task->stack);
@@ -299,7 +306,8 @@ void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
 			microblaze_unwind_inner(task,
 						(unsigned long) &_switch_to,
 						cpu_context->r1,
-						cpu_context->r15, trace);
+						cpu_context->r15,
+						trace, loglvl);
 		}
 	} else {
 		unsigned long pc, fp;
@@ -314,7 +322,7 @@ void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
 		);
 
 		/* Since we are not a leaf function, use leaf_return = 0 */
-		microblaze_unwind_inner(current, pc, fp, 0, trace);
+		microblaze_unwind_inner(current, pc, fp, 0, trace, loglvl);
 	}
 }
 
-- 
2.26.0

[PATCHv3 19/50] microblaze: Add loglvl to microblaze_unwind()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level parameter to microblaze_unwind() as a preparation to add
show_stack_loglvl().

Cc: Michal Simek <monstr@monstr.eu>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/microblaze/include/asm/unwind.h | 3 ++-
 arch/microblaze/kernel/stacktrace.c  | 4 ++--
 arch/microblaze/kernel/traps.c       | 2 +-
 arch/microblaze/kernel/unwind.c      | 6 +++---
 4 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/microblaze/include/asm/unwind.h b/arch/microblaze/include/asm/unwind.h
index c327d673622a..3db81777a887 100644
--- a/arch/microblaze/include/asm/unwind.h
+++ b/arch/microblaze/include/asm/unwind.h
@@ -20,7 +20,8 @@ extern struct trap_handler_info microblaze_trap_handlers;
 extern const char _hw_exception_handler;
 extern const char ex_handler_unhandled;
 
-void microblaze_unwind(struct task_struct *task, struct stack_trace *trace);
+void microblaze_unwind(struct task_struct *task, struct stack_trace *trace,
+		       const char *loglvl);
 
 #endif	/* __MICROBLAZE_UNWIND_H */
 
diff --git a/arch/microblaze/kernel/stacktrace.c b/arch/microblaze/kernel/stacktrace.c
index b4debe283a79..b266c4d6ed9d 100644
--- a/arch/microblaze/kernel/stacktrace.c
+++ b/arch/microblaze/kernel/stacktrace.c
@@ -20,12 +20,12 @@ void save_stack_trace(struct stack_trace *trace)
 {
 	/* Exclude our helper functions from the trace*/
 	trace->skip += 2;
-	microblaze_unwind(NULL, trace);
+	microblaze_unwind(NULL, trace, "");
 }
 EXPORT_SYMBOL_GPL(save_stack_trace);
 
 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
 {
-	microblaze_unwind(tsk, trace);
+	microblaze_unwind(tsk, trace, "");
 }
 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c
index 45bbba9d919f..be726ee120fb 100644
--- a/arch/microblaze/kernel/traps.c
+++ b/arch/microblaze/kernel/traps.c
@@ -68,7 +68,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
 		       words_to_show << 2, 0);
 	pr_info("\n\nCall Trace:\n");
-	microblaze_unwind(task, NULL);
+	microblaze_unwind(task, NULL, KERN_INFO);
 	pr_info("\n");
 
 	if (!task)
diff --git a/arch/microblaze/kernel/unwind.c b/arch/microblaze/kernel/unwind.c
index 804bf0c99d8b..778a761af0a7 100644
--- a/arch/microblaze/kernel/unwind.c
+++ b/arch/microblaze/kernel/unwind.c
@@ -287,11 +287,11 @@ static void microblaze_unwind_inner(struct task_struct *task,
  * @task  : Task whose stack we are to unwind (NULL == current)
  * @trace : Where to store stack backtrace (PC values).
  *	    NULL == print backtrace to kernel log
+ * @loglvl : Used for printk log level if (trace == NULL).
  */
-void microblaze_unwind(struct task_struct *task, struct stack_trace *trace)
+void microblaze_unwind(struct task_struct *task, struct stack_trace *trace,
+		       const char *loglvl)
 {
-	const char *loglvl = KERN_INFO;
-
 	if (task) {
 		if (task == current) {
 			const struct pt_regs *regs = task_pt_regs(task);
-- 
2.26.0

[PATCHv3 20/50] microblaze: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Michal Simek <monstr@monstr.eu>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/microblaze/kernel/traps.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c
index be726ee120fb..149ae534937e 100644
--- a/arch/microblaze/kernel/traps.c
+++ b/arch/microblaze/kernel/traps.c
@@ -31,7 +31,8 @@ static int __init kstack_setup(char *s)
 }
 __setup("kstack=", kstack_setup);
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	unsigned long words_to_show;
 	u32 fp = (u32) sp;
@@ -50,7 +51,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	if (kstack_depth_to_print && (words_to_show > kstack_depth_to_print))
 		words_to_show = kstack_depth_to_print;
 
-	pr_info("Kernel Stack:\n");
+	printk("%sKernel Stack:\n", loglvl);
 
 	/*
 	 * Make the first line an 'odd' size if necessary to get
@@ -65,14 +66,19 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 			words_to_show -= line1_words;
 		}
 	}
-	print_hex_dump(KERN_INFO, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
+	print_hex_dump(loglvl, "", DUMP_PREFIX_ADDRESS, 32, 4, (void *)fp,
 		       words_to_show << 2, 0);
-	pr_info("\n\nCall Trace:\n");
-	microblaze_unwind(task, NULL, KERN_INFO);
-	pr_info("\n");
+	printk("%s\n\nCall Trace:\n", loglvl);
+	microblaze_unwind(task, NULL, loglvl);
+	printk("%s\n", loglvl);
 
 	if (!task)
 		task = current;
 
 	debug_show_held_locks(task);
 }
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_INFO);
+}
-- 
2.26.0

[PATCHv3 21/50] mips: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: James Hogan <jhogan@kernel.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/mips/kernel/traps.c | 41 +++++++++++++++++++++++-----------------
 1 file changed, 24 insertions(+), 17 deletions(-)

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index de05503c680c..077aabbd6b9f 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -106,26 +106,26 @@ void (*board_bind_eic_interrupt)(int irq, int regset);
 void (*board_ebase_setup)(void);
 void(*board_cache_error_setup)(void);
 
-static void show_raw_backtrace(unsigned long reg29)
+static void show_raw_backtrace(unsigned long reg29, const char *loglvl)
 {
 	unsigned long *sp = (unsigned long *)(reg29 & ~3);
 	unsigned long addr;
 
-	printk("Call Trace:");
+	printk("%sCall Trace:", loglvl);
 #ifdef CONFIG_KALLSYMS
-	printk("\n");
+	printk("%s\n", loglvl);
 #endif
 	while (!kstack_end(sp)) {
 		unsigned long __user *p =
 			(unsigned long __user *)(unsigned long)sp++;
 		if (__get_user(addr, p)) {
-			printk(" (Bad stack address)");
+			printk("%s (Bad stack address)", loglvl);
 			break;
 		}
 		if (__kernel_text_address(addr))
-			print_ip_sym(KERN_DEFAULT, addr);
+			print_ip_sym(loglvl, addr);
 	}
-	printk("\n");
+	printk("%s\n", loglvl);
 }
 
 #ifdef CONFIG_KALLSYMS
@@ -138,7 +138,8 @@ static int __init set_raw_show_trace(char *str)
 __setup("raw_show_trace", set_raw_show_trace);
 #endif
 
-static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
+static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
+			   const char *loglvl)
 {
 	unsigned long sp = regs->regs[29];
 	unsigned long ra = regs->regs[31];
@@ -148,12 +149,12 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
 		task = current;
 
 	if (raw_show_trace || user_mode(regs) || !__kernel_text_address(pc)) {
-		show_raw_backtrace(sp);
+		show_raw_backtrace(sp, loglvl);
 		return;
 	}
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	do {
-		print_ip_sym(KERN_DEFAULT, pc);
+		print_ip_sym(loglvl, pc);
 		pc = unwind_stack(task, &sp, pc, &ra);
 	} while (pc);
 	pr_cont("\n");
@@ -164,19 +165,19 @@ static void show_backtrace(struct task_struct *task, const struct pt_regs *regs)
  * with at least a bit of error checking ...
  */
 static void show_stacktrace(struct task_struct *task,
-	const struct pt_regs *regs)
+	const struct pt_regs *regs, const char *loglvl)
 {
 	const int field = 2 * sizeof(unsigned long);
 	long stackdata;
 	int i;
 	unsigned long __user *sp = (unsigned long __user *)regs->regs[29];
 
-	printk("Stack :");
+	printk("%sStack :", loglvl);
 	i = 0;
 	while ((unsigned long) sp & (PAGE_SIZE - 1)) {
 		if (i && ((i % (64 / field)) == 0)) {
 			pr_cont("\n");
-			printk("       ");
+			printk("%s       ", loglvl);
 		}
 		if (i > 39) {
 			pr_cont(" ...");
@@ -192,10 +193,11 @@ static void show_stacktrace(struct task_struct *task,
 		i++;
 	}
 	pr_cont("\n");
-	show_backtrace(task, regs);
+	show_backtrace(task, regs, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	struct pt_regs regs;
 	mm_segment_t old_fs = get_fs();
@@ -219,10 +221,15 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	 * the stack in the kernel (not user) address space.
 	 */
 	set_fs(KERNEL_DS);
-	show_stacktrace(task, &regs);
+	show_stacktrace(task, &regs, loglvl);
 	set_fs(old_fs);
 }
 
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT)
+}
+
 static void show_code(unsigned int __user *pc)
 {
 	long i;
@@ -371,7 +378,7 @@ void show_registers(struct pt_regs *regs)
 	if (!user_mode(regs))
 		/* Necessary for getting the correct stack content */
 		set_fs(KERNEL_DS);
-	show_stacktrace(current, regs);
+	show_stacktrace(current, regs, KERN_DEFAULT);
 	show_code((unsigned int __user *) regs->cp0_epc);
 	printk("\n");
 	set_fs(old_fs);
-- 
2.26.0

[PATCHv3 22/50] nds32: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Greentime Hu <green.hu@gmail.com>
Cc: Vincent Chen <deanbo422@gmail.com>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/nds32/kernel/traps.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index 40625760a125..90f12582c218 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c
@@ -97,18 +97,19 @@ static void dump_instr(struct pt_regs *regs)
 }
 
 #define LOOP_TIMES (100)
-static void __dump(struct task_struct *tsk, unsigned long *base_reg)
+static void __dump(struct task_struct *tsk, unsigned long *base_reg,
+		   const char *loglvl)
 {
 	unsigned long ret_addr;
 	int cnt = LOOP_TIMES, graph = 0;
-	pr_emerg("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	if (!IS_ENABLED(CONFIG_FRAME_POINTER)) {
 		while (!kstack_end(base_reg)) {
 			ret_addr = *base_reg++;
 			if (__kernel_text_address(ret_addr)) {
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(KERN_EMERG, ret_addr);
+				print_ip_sym(loglvl, ret_addr);
 			}
 			if (--cnt < 0)
 				break;
@@ -124,17 +125,18 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg)
 
 				ret_addr = ftrace_graph_ret_addr(
 						tsk, &graph, ret_addr, NULL);
-				print_ip_sym(KERN_EMERG, ret_addr);
+				print_ip_sym(loglvl, ret_addr);
 			}
 			if (--cnt < 0)
 				break;
 			base_reg = (unsigned long *)next_fp;
 		}
 	}
-	pr_emerg("\n");
+	printk("%s\n", loglvl);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
 	unsigned long *base_reg;
 
@@ -151,10 +153,15 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 		else
 			__asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(base_reg));
 	}
-	__dump(tsk, base_reg);
+	__dump(tsk, base_reg, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_EMERG);
+}
+
 DEFINE_SPINLOCK(die_lock);
 
 /*
-- 
2.26.0

[PATCHv3 23/50] nios2: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Ley Foon Tan <lftan@altera.com>
Cc: nios2-dev@lists.rocketboards.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/nios2/kernel/traps.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
index 486db793923c..08071caa9b36 100644
--- a/arch/nios2/kernel/traps.c
+++ b/arch/nios2/kernel/traps.c
@@ -52,12 +52,14 @@ void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
 }
 
 /*
- * The show_stack is an external API which we do not use ourselves.
+ * The show_stack(), show_stack_loglvl() are external API
+ * which we do not use ourselves.
  */
 
 int kstack_depth_to_print = 48;
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long *endstack, addr;
 	int i;
@@ -72,16 +74,16 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	addr = (unsigned long) stack;
 	endstack = (unsigned long *) PAGE_ALIGN(addr);
 
-	pr_emerg("Stack from %08lx:", (unsigned long)stack);
+	printk("%sStack from %08lx:", loglvl, (unsigned long)stack);
 	for (i = 0; i < kstack_depth_to_print; i++) {
 		if (stack + 1 > endstack)
 			break;
 		if (i % 8 == 0)
-			pr_emerg("\n       ");
-		pr_emerg(" %08lx", *stack++);
+			printk("%s\n       ", loglvl);
+		printk("%s %08lx", loglvl, *stack++);
 	}
 
-	pr_emerg("\nCall Trace:");
+	printk("%s\nCall Trace:", loglvl);
 	i = 0;
 	while (stack + 1 <= endstack) {
 		addr = *stack++;
@@ -97,11 +99,16 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 		     (addr <= (unsigned long) _etext))) {
 			if (i % 4 == 0)
 				pr_emerg("\n       ");
-			pr_emerg(" [<%08lx>]", addr);
+			printk("%s [<%08lx>]", loglvl, addr);
 			i++;
 		}
 	}
-	pr_emerg("\n");
+	printk("%s\n", loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_EMERG);
 }
 
 void __init trap_init(void)
-- 
2.26.0

[PATCHv3 24/50] openrisc: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: openrisc@lists.librecores.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/openrisc/kernel/traps.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index c11aa2e17ce0..3b7978a22d68 100644
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c
@@ -41,18 +41,26 @@ unsigned long __user *lwa_addr;
 
 void print_trace(void *data, unsigned long addr, int reliable)
 {
-	pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
+	const char *loglvl = data;
+
+	printk("%s[<%p>] %s%pS\n", loglvl, (void *) addr, reliable ? "" : "? ",
 	       (void *) addr);
 }
 
 /* displays a short stack trace */
-void show_stack(struct task_struct *task, unsigned long *esp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
+		const char *loglvl)
 {
 	if (esp == NULL)
 		esp = (unsigned long *)&esp;
 
-	pr_emerg("Call trace:\n");
-	unwind_stack(NULL, esp, print_trace);
+	printk("%sCall trace:\n", loglvl);
+	unwind_stack((void *)loglvl, esp, print_trace);
+}
+
+void show_stack(struct task_struct *task, unsigned long *esp)
+{
+	show_stack_loglvl(task, esp, KERN_EMERG);
 }
 
 void show_registers(struct pt_regs *regs)
-- 
2.26.0

Re: [PATCHv3 24/50] openrisc: Add show_stack_loglvl()

[Stafford Horne]

On Sat, Apr 18, 2020 at 09:19:18PM +0100, Dmitry Safonov wrote:
> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with

Instead of realization I would say "Implementation".

> lower log level or higher than the stacktrace (depending on
> a platform or user).
> 
> Furthermore, it forces the logic decision from user to an architecture
> side. In result, some users as sysrq/kdb/etc are doing tricks with
> temporary rising console_loglevel while printing their messages.
> And in result it not only may print unwanted messages from other CPUs,
> but also omit printing at all in the unlucky case where the printk()
> was deferred.
> 
> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
> an easier approach than introducing more printk buffers.
> Also, it will consolidate printings with headers.
> 
> Introduce show_stack_loglvl(), that eventually will substitute
> show_stack().

Will you do the work to replace show_stack(), when is that planned?

Other than that small comment this looks fine.

Acked-by: Stafford Horne <shorne@gmail.com>


> Cc: Jonas Bonn <jonas@southpole.se>
> Cc: Stafford Horne <shorne@gmail.com>
> Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
> Cc: openrisc@lists.librecores.org
> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
> Signed-off-by: Dmitry Safonov <dima@arista.com>

Re: [PATCHv3 24/50] openrisc: Add show_stack_loglvl()

[Dmitry Safonov]

On 4/19/20 9:57 PM, Stafford Horne wrote:
> On Sat, Apr 18, 2020 at 09:19:18PM +0100, Dmitry Safonov wrote:
>> Currently, the log-level of show_stack() depends on a platform
>> realization. It creates situations where the headers are printed with
> 
> Instead of realization I would say "Implementation".
> 
>> lower log level or higher than the stacktrace (depending on
>> a platform or user).
>>
>> Furthermore, it forces the logic decision from user to an architecture
>> side. In result, some users as sysrq/kdb/etc are doing tricks with
>> temporary rising console_loglevel while printing their messages.
>> And in result it not only may print unwanted messages from other CPUs,
>> but also omit printing at all in the unlucky case where the printk()
>> was deferred.
>>
>> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
>> an easier approach than introducing more printk buffers.
>> Also, it will consolidate printings with headers.
>>
>> Introduce show_stack_loglvl(), that eventually will substitute
>> show_stack().
> 
> Will you do the work to replace show_stack(), when is that planned?

In the patch 50/50 from the series:
https://lore.kernel.org/lkml/20200418201944.482088-51-dima@arista.com/

> 
> Other than that small comment this looks fine.
> 
> Acked-by: Stafford Horne <shorne@gmail.com>
Thank you,
          Dmitry

[PATCHv3 25/50] parisc: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: linux-parisc@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/parisc/kernel/traps.c | 28 +++++++++++++++++-----------
 1 file changed, 17 insertions(+), 11 deletions(-)

diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 82fc01189488..c2411de3730f 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -49,7 +49,7 @@
 #include "../math-emu/math-emu.h"	/* for handle_fpe() */
 
 static void parisc_show_stack(struct task_struct *task,
-	struct pt_regs *regs);
+	struct pt_regs *regs, const char *loglvl);
 
 static int printbinary(char *buf, unsigned long x, int nbits)
 {
@@ -155,7 +155,7 @@ void show_regs(struct pt_regs *regs)
 		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
 		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
 
-		parisc_show_stack(current, regs);
+		parisc_show_stack(current, regs, KERN_DEFAULT);
 	}
 }
 
@@ -170,37 +170,43 @@ static DEFINE_RATELIMIT_STATE(_hppa_rs,
 }
 
 
-static void do_show_stack(struct unwind_frame_info *info)
+static void do_show_stack(struct unwind_frame_info *info, const char *loglvl)
 {
 	int i = 1;
 
-	printk(KERN_CRIT "Backtrace:\n");
+	printk("%sBacktrace:\n", loglvl);
 	while (i <= MAX_UNWIND_ENTRIES) {
 		if (unwind_once(info) < 0 || info->ip == 0)
 			break;
 
 		if (__kernel_text_address(info->ip)) {
-			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
-				info->ip, (void *) info->ip);
+			printk("%s [<" RFMT ">] %pS\n",
+				loglvl, info->ip, (void *) info->ip);
 			i++;
 		}
 	}
-	printk(KERN_CRIT "\n");
+	printk("%s\n", loglvl);
 }
 
 static void parisc_show_stack(struct task_struct *task,
-	struct pt_regs *regs)
+	struct pt_regs *regs, const char *loglvl)
 {
 	struct unwind_frame_info info;
 
 	unwind_frame_init_task(&info, task, regs);
 
-	do_show_stack(&info);
+	do_show_stack(&info, loglvl);
+}
+
+void show_stack_loglvl(struct task_struct *t, unsigned long *sp,
+		       const char *loglvl)
+{
+	parisc_show_stack(t, NULL, loglvl);
 }
 
 void show_stack(struct task_struct *t, unsigned long *sp)
 {
-	parisc_show_stack(t, NULL);
+	show_stack_loglvl(t, sp, KERN_CRIT)
 }
 
 int is_valid_bugaddr(unsigned long iaoq)
@@ -446,7 +452,7 @@ void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long o
 		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
 		struct unwind_frame_info info;
 		unwind_frame_init(&info, current, regs);
-		do_show_stack(&info);
+		do_show_stack(&info, KERN_CRIT);
 	}
 
 	printk("\n");
-- 
2.26.0

Re: [PATCHv3 25/50] parisc: Add show_stack_loglvl()

[Helge Deller]

On 18.04.20 22:19, Dmitry Safonov wrote:
> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with
> lower log level or higher than the stacktrace (depending on
> a platform or user).
>
> Furthermore, it forces the logic decision from user to an architecture
> side. In result, some users as sysrq/kdb/etc are doing tricks with
> temporary rising console_loglevel while printing their messages.
> And in result it not only may print unwanted messages from other CPUs,
> but also omit printing at all in the unlucky case where the printk()
> was deferred.
>
> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
> an easier approach than introducing more printk buffers.
> Also, it will consolidate printings with headers.
>
> Introduce show_stack_loglvl(), that eventually will substitute
> show_stack().
>
> Cc: Helge Deller <deller@gmx.de>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: linux-parisc@vger.kernel.org
> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---
>  arch/parisc/kernel/traps.c | 28 +++++++++++++++++-----------
>  1 file changed, 17 insertions(+), 11 deletions(-)

Acked-by: Helge Deller <deller@gmx.de>

Thanks!
Helge


>
> diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
> index 82fc01189488..c2411de3730f 100644
> --- a/arch/parisc/kernel/traps.c
> +++ b/arch/parisc/kernel/traps.c
> @@ -49,7 +49,7 @@
>  #include "../math-emu/math-emu.h"	/* for handle_fpe() */
>
>  static void parisc_show_stack(struct task_struct *task,
> -	struct pt_regs *regs);
> +	struct pt_regs *regs, const char *loglvl);
>
>  static int printbinary(char *buf, unsigned long x, int nbits)
>  {
> @@ -155,7 +155,7 @@ void show_regs(struct pt_regs *regs)
>  		printk("%s IAOQ[1]: %pS\n", level, (void *) regs->iaoq[1]);
>  		printk("%s RP(r2): %pS\n", level, (void *) regs->gr[2]);
>
> -		parisc_show_stack(current, regs);
> +		parisc_show_stack(current, regs, KERN_DEFAULT);
>  	}
>  }
>
> @@ -170,37 +170,43 @@ static DEFINE_RATELIMIT_STATE(_hppa_rs,
>  }
>
>
> -static void do_show_stack(struct unwind_frame_info *info)
> +static void do_show_stack(struct unwind_frame_info *info, const char *loglvl)
>  {
>  	int i = 1;
>
> -	printk(KERN_CRIT "Backtrace:\n");
> +	printk("%sBacktrace:\n", loglvl);
>  	while (i <= MAX_UNWIND_ENTRIES) {
>  		if (unwind_once(info) < 0 || info->ip == 0)
>  			break;
>
>  		if (__kernel_text_address(info->ip)) {
> -			printk(KERN_CRIT " [<" RFMT ">] %pS\n",
> -				info->ip, (void *) info->ip);
> +			printk("%s [<" RFMT ">] %pS\n",
> +				loglvl, info->ip, (void *) info->ip);
>  			i++;
>  		}
>  	}
> -	printk(KERN_CRIT "\n");
> +	printk("%s\n", loglvl);
>  }
>
>  static void parisc_show_stack(struct task_struct *task,
> -	struct pt_regs *regs)
> +	struct pt_regs *regs, const char *loglvl)
>  {
>  	struct unwind_frame_info info;
>
>  	unwind_frame_init_task(&info, task, regs);
>
> -	do_show_stack(&info);
> +	do_show_stack(&info, loglvl);
> +}
> +
> +void show_stack_loglvl(struct task_struct *t, unsigned long *sp,
> +		       const char *loglvl)
> +{
> +	parisc_show_stack(t, NULL, loglvl);
>  }
>
>  void show_stack(struct task_struct *t, unsigned long *sp)
>  {
> -	parisc_show_stack(t, NULL);
> +	show_stack_loglvl(t, sp, KERN_CRIT)
>  }
>
>  int is_valid_bugaddr(unsigned long iaoq)
> @@ -446,7 +452,7 @@ void parisc_terminate(char *msg, struct pt_regs *regs, int code, unsigned long o
>  		/* show_stack(NULL, (unsigned long *)regs->gr[30]); */
>  		struct unwind_frame_info info;
>  		unwind_frame_init(&info, current, regs);
> -		do_show_stack(&info);
> +		do_show_stack(&info, KERN_CRIT);
>  	}
>
>  	printk("\n");
>

[PATCHv3 26/50] powerpc: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/powerpc/kernel/process.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 9c21288f8645..6ad438d59796 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -2068,7 +2068,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack(struct task_struct *tsk, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack,
+		       const char *loglvl)
 {
 	unsigned long sp, ip, lr, newsp;
 	int count = 0;
@@ -2093,7 +2094,7 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	}
 
 	lr = 0;
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	do {
 		if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
 			break;
@@ -2102,7 +2103,8 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 		newsp = stack[0];
 		ip = stack[STACK_FRAME_LR_SAVE];
 		if (!firstframe || ip != lr) {
-			printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
+			printk("%s["REG"] ["REG"] %pS",
+				loglvl, sp, ip, (void *)ip);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 			ret_addr = ftrace_graph_ret_addr(current,
 						&ftrace_idx, ip, stack);
@@ -2124,8 +2126,9 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 			struct pt_regs *regs = (struct pt_regs *)
 				(sp + STACK_FRAME_OVERHEAD);
 			lr = regs->link;
-			printk("--- interrupt: %lx at %pS\n    LR = %pS\n",
-			       regs->trap, (void *)regs->nip, (void *)lr);
+			printk("%s--- interrupt: %lx at %pS\n    LR = %pS\n",
+			       loglvl, regs->trap,
+			       (void *)regs->nip, (void *)lr);
 			firstframe = 1;
 		}
 
@@ -2135,6 +2138,11 @@ void show_stack(struct task_struct *tsk, unsigned long *stack)
 	put_task_stack(tsk);
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *stack)
+{
+	show_stack_loglvl(tsk, stack, KERN_DEFAULT);
+}
+
 #ifdef CONFIG_PPC64
 /* Called with hard IRQs off */
 void notrace __ppc64_runlatch_on(void)
-- 
2.26.0

[PATCHv3 27/50] riscv: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: linux-riscv@lists.infradead.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/riscv/kernel/stacktrace.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index eeee844fb93d..05bf537310a8 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -99,16 +99,23 @@ static void notrace walk_stackframe(struct task_struct *task,
 
 static bool print_trace_address(unsigned long pc, void *arg)
 {
-	print_ip_sym(KERN_DEFAULT, pc);
+	const char *loglvl = arg;
+
+	print_ip_sym(loglvl, pc);
 	return false;
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	pr_cont("Call Trace:\n");
-	walk_stackframe(task, NULL, print_trace_address, NULL);
+	walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
 }
 
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
+}
 
 static bool save_wchan(unsigned long pc, void *arg)
 {
-- 
2.26.0

[PATCHv3 28/50] s390: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/s390/kernel/dumpstack.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index 2c122d8bab93..887a054919fc 100644
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -126,18 +126,24 @@ int get_stack_info(unsigned long sp, struct task_struct *task,
 	return -EINVAL;
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	struct unwind_state state;
 
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	unwind_for_each_frame(&state, task, NULL, (unsigned long) stack)
-		printk(state.reliable ? " [<%016lx>] %pSR \n" :
-					"([<%016lx>] %pSR)\n",
-		       state.ip, (void *) state.ip);
+		printk(state.reliable ? "%s [<%016lx>] %pSR \n" :
+					"%s([<%016lx>] %pSR)\n",
+		       loglvl, state.ip, (void *) state.ip);
 	debug_show_held_locks(task ? : current);
 }
 
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_DEFAULT);
+}
+
 static void show_last_breaking_event(struct pt_regs *regs)
 {
 	printk("Last Breaking-Event-Address:\n");
-- 
2.26.0

[PATCHv3 29/50] sh: Add loglvl to dump_mem()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to dump_mem() as a preparation to introduce
show_stack_loglvl().

Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-sh@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/sh/include/asm/kdebug.h |  3 ++-
 arch/sh/kernel/dumpstack.c   | 17 +++++++++--------
 arch/sh/kernel/traps.c       |  4 ++--
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/arch/sh/include/asm/kdebug.h b/arch/sh/include/asm/kdebug.h
index 5212f5fcd752..de8693fabb1d 100644
--- a/arch/sh/include/asm/kdebug.h
+++ b/arch/sh/include/asm/kdebug.h
@@ -13,6 +13,7 @@ enum die_val {
 
 /* arch/sh/kernel/dumpstack.c */
 extern void printk_address(unsigned long address, int reliable);
-extern void dump_mem(const char *str, unsigned long bottom, unsigned long top);
+extern void dump_mem(const char *str, const char *loglvl,
+		     unsigned long bottom, unsigned long top);
 
 #endif /* __ASM_SH_KDEBUG_H */
diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index 9f1c9c11d62d..6784b914fba0 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -16,30 +16,31 @@
 #include <asm/unwinder.h>
 #include <asm/stacktrace.h>
 
-void dump_mem(const char *str, unsigned long bottom, unsigned long top)
+void dump_mem(const char *str, const char *loglvl,
+	      unsigned long bottom, unsigned long top)
 {
 	unsigned long p;
 	int i;
 
-	printk("%s(0x%08lx to 0x%08lx)\n", str, bottom, top);
+	printk("%s%s(0x%08lx to 0x%08lx)\n", loglvl, str, bottom, top);
 
 	for (p = bottom & ~31; p < top; ) {
-		printk("%04lx: ", p & 0xffff);
+		printk("%s%04lx: ", loglvl,  p & 0xffff);
 
 		for (i = 0; i < 8; i++, p += 4) {
 			unsigned int val;
 
 			if (p < bottom || p >= top)
-				printk("         ");
+				printk("%s         ", loglvl);
 			else {
 				if (__get_user(val, (unsigned int __user *)p)) {
-					printk("\n");
+					printk("%s\n", loglvl);
 					return;
 				}
-				printk("%08x ", val);
+				printk("%s%08x ", loglvl, val);
 			}
 		}
-		printk("\n");
+		printk("%s\n", loglvl);
 	}
 }
 
@@ -156,7 +157,7 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 		sp = (unsigned long *)tsk->thread.sp;
 
 	stack = (unsigned long)sp;
-	dump_mem("Stack: ", stack, THREAD_SIZE +
+	dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
 		 (unsigned long)task_stack_page(tsk));
 	show_trace(tsk, sp, NULL);
 }
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 63cf17bc760d..faad65409075 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -38,8 +38,8 @@ void die(const char *str, struct pt_regs *regs, long err)
 			task_pid_nr(current), task_stack_page(current) + 1);
 
 	if (!user_mode(regs) || in_interrupt())
-		dump_mem("Stack: ", regs->regs[15], THREAD_SIZE +
-			 (unsigned long)task_stack_page(current));
+		dump_mem("Stack: ", KERN_DEFAULT, regs->regs[15],
+			THREAD_SIZE + (unsigned long)task_stack_page(current));
 
 	notify_die(DIE_OOPS, str, regs, err, 255, SIGSEGV);
 
-- 
2.26.0

[PATCHv3 30/50] sh: Remove needless printk()

[Dmitry Safonov]

Currently `data' is always an empty line "".
No need for additional printk() call.

Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-sh@vger.kernel.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/sh/kernel/dumpstack.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index 6784b914fba0..2c1a78e5776b 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -118,7 +118,6 @@ static int print_trace_stack(void *data, char *name)
  */
 static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
-	printk("%s", (char *)data);
 	printk_address(addr, reliable);
 }
 
-- 
2.26.0

[PATCHv3 31/50] sh: Add loglvl to printk_address()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to printk_address() as a preparation to introduce
show_stack_loglvl().

As a good side-effect show_fault_oops() now prints the address with
KERN_EMREG as the rest of output, making sure there won't be situation
where "PC: " is printed without actual address.

Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/sh/include/asm/kdebug.h | 3 ++-
 arch/sh/kernel/dumpstack.c   | 6 +++---
 arch/sh/mm/fault.c           | 2 +-
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/arch/sh/include/asm/kdebug.h b/arch/sh/include/asm/kdebug.h
index de8693fabb1d..960545306afa 100644
--- a/arch/sh/include/asm/kdebug.h
+++ b/arch/sh/include/asm/kdebug.h
@@ -12,7 +12,8 @@ enum die_val {
 };
 
 /* arch/sh/kernel/dumpstack.c */
-extern void printk_address(unsigned long address, int reliable);
+extern void printk_address(unsigned long address, int reliable,
+			   const char *loglvl);
 extern void dump_mem(const char *str, const char *loglvl,
 		     unsigned long bottom, unsigned long top);
 
diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index 2c1a78e5776b..959064b90055 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -44,9 +44,9 @@ void dump_mem(const char *str, const char *loglvl,
 	}
 }
 
-void printk_address(unsigned long address, int reliable)
+void printk_address(unsigned long address, int reliable, const char *loglvl)
 {
-	printk(" [<%p>] %s%pS\n", (void *) address,
+	printk("%s [<%p>] %s%pS\n", loglvl, (void *) address,
 			reliable ? "" : "? ", (void *) address);
 }
 
@@ -118,7 +118,7 @@ static int print_trace_stack(void *data, char *name)
  */
 static void print_trace_address(void *data, unsigned long addr, int reliable)
 {
-	printk_address(addr, reliable);
+	printk_address(addr, reliable, (char *)data);
 }
 
 static const struct stacktrace_ops print_trace_ops = {
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
index 5f23d7907597..f5da8f5ea389 100644
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -196,7 +196,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long address)
 
 	printk(KERN_CONT " at %08lx\n", address);
 	printk(KERN_ALERT "PC:");
-	printk_address(regs->pc, 1);
+	printk_address(regs->pc, 1, KERN_ALERT);
 
 	show_pte(NULL, address);
 }
-- 
2.26.0

Re: [PATCHv3 31/50] sh: Add loglvl to printk_address()

[Andrew Morton]

On Sat, 18 Apr 2020 21:19:25 +0100 Dmitry Safonov <dima@arista.com> wrote:

> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with
> lower log level or higher than the stacktrace (depending on
> a platform or user).
> 
> Furthermore, it forces the logic decision from user to an architecture
> side. In result, some users as sysrq/kdb/etc are doing tricks with
> temporary rising console_loglevel while printing their messages.
> And in result it not only may print unwanted messages from other CPUs,
> but also omit printing at all in the unlucky case where the printk()
> was deferred.
> 
> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
> an easier approach than introducing more printk buffers.
> Also, it will consolidate printings with headers.
> 
> Add log level argument to printk_address() as a preparation to introduce
> show_stack_loglvl().
> 
> As a good side-effect show_fault_oops() now prints the address with
> KERN_EMREG as the rest of output, making sure there won't be situation
> where "PC: " is printed without actual address.
> 
> --- a/arch/sh/include/asm/kdebug.h
> +++ b/arch/sh/include/asm/kdebug.h
> @@ -12,7 +12,8 @@ enum die_val {
>  };
>  
>  /* arch/sh/kernel/dumpstack.c */
> -extern void printk_address(unsigned long address, int reliable);
> +extern void printk_address(unsigned long address, int reliable,
> +			   const char *loglvl);
>  extern void dump_mem(const char *str, const char *loglvl,
>  		     unsigned long bottom, unsigned long top);
>  
> ...
>
> --- a/arch/sh/mm/fault.c
> +++ b/arch/sh/mm/fault.c
> @@ -196,7 +196,7 @@ show_fault_oops(struct pt_regs *regs, unsigned long address)
>  
>  	printk(KERN_CONT " at %08lx\n", address);
>  	printk(KERN_ALERT "PC:");
> -	printk_address(regs->pc, 1);
> +	printk_address(regs->pc, 1, KERN_ALERT);
>  

It would be more intuitive to do

	printk_address(KERN_ALERT, regs->pc, 1);

because the loglevel always comes first.

I guess it doesn't matter much, as sh seems to be rather dead.

Re: [PATCHv3 31/50] sh: Add loglvl to printk_address()

[Rob Landley]

On 4/20/20 5:52 PM, Andrew Morton wrote:
> I guess it doesn't matter much, as sh seems to be rather dead.

The j-core guys are using it.

Rob

Re: [PATCHv3 31/50] sh: Add loglvl to printk_address()

[Rich Felker]

On Sat, Apr 25, 2020 at 11:06:41AM -0500, Rob Landley wrote:
> On 4/20/20 5:52 PM, Andrew Morton wrote:
> > I guess it doesn't matter much, as sh seems to be rather dead.
> 
> The j-core guys are using it.

Yes. There are also Debian/SH folks using classic SH4.

Rich

[PATCHv3 32/50] sh: Add loglvl to show_trace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level parameter to show_trace() as a preparation to introduce
show_stack_loglvl().

Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/sh/include/asm/processor_32.h |  2 +-
 arch/sh/kernel/dumpstack.c         | 10 +++++-----
 arch/sh/kernel/process_32.c        |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/arch/sh/include/asm/processor_32.h b/arch/sh/include/asm/processor_32.h
index 0e0ecc0132e3..d44409413418 100644
--- a/arch/sh/include/asm/processor_32.h
+++ b/arch/sh/include/asm/processor_32.h
@@ -171,7 +171,7 @@ static __inline__ void enable_fpu(void)
 #define thread_saved_pc(tsk)	(tsk->thread.pc)
 
 void show_trace(struct task_struct *tsk, unsigned long *sp,
-		struct pt_regs *regs);
+		struct pt_regs *regs, const char *loglvl);
 
 #ifdef CONFIG_DUMP_CODE
 void show_code(struct pt_regs *regs);
diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index 959064b90055..d488a47a1f0f 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -127,16 +127,16 @@ static const struct stacktrace_ops print_trace_ops = {
 };
 
 void show_trace(struct task_struct *tsk, unsigned long *sp,
-		struct pt_regs *regs)
+		struct pt_regs *regs, const char *loglvl)
 {
 	if (regs && user_mode(regs))
 		return;
 
-	printk("\nCall trace:\n");
+	printk("%s\nCall trace:\n", loglvl);
 
-	unwind_stack(tsk, regs, sp, &print_trace_ops, "");
+	unwind_stack(tsk, regs, sp, &print_trace_ops, (void *)loglvl);
 
-	printk("\n");
+	printk("%s\n", loglvl);
 
 	if (!tsk)
 		tsk = current;
@@ -158,5 +158,5 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 	stack = (unsigned long)sp;
 	dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
 		 (unsigned long)task_stack_page(tsk));
-	show_trace(tsk, sp, NULL);
+	show_trace(tsk, sp, NULL, KERN_DEFAULT);
 }
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index a094633874c3..456cc8d171f7 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -59,7 +59,7 @@ void show_regs(struct pt_regs * regs)
 	printk("MACH: %08lx MACL: %08lx GBR : %08lx PR  : %08lx\n",
 	       regs->mach, regs->macl, regs->gbr, regs->pr);
 
-	show_trace(NULL, (unsigned long *)regs->regs[15], regs);
+	show_trace(NULL, (unsigned long *)regs->regs[15], regs, KERN_DEFAULT);
 	show_code(regs);
 }
 
-- 
2.26.0

[PATCHv3 33/50] sh: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Rich Felker <dalias@libc.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: linux-sh@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/sh/kernel/dumpstack.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index d488a47a1f0f..cc51e9d74667 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -144,7 +144,8 @@ void show_trace(struct task_struct *tsk, unsigned long *sp,
 	debug_show_held_locks(tsk);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
 	unsigned long stack;
 
@@ -156,7 +157,12 @@ void show_stack(struct task_struct *tsk, unsigned long *sp)
 		sp = (unsigned long *)tsk->thread.sp;
 
 	stack = (unsigned long)sp;
-	dump_mem("Stack: ", KERN_DEFAULT, stack, THREAD_SIZE +
+	dump_mem("Stack: ", loglvl, stack, THREAD_SIZE +
 		 (unsigned long)task_stack_page(tsk));
-	show_trace(tsk, sp, NULL, KERN_DEFAULT);
+	show_trace(tsk, sp, NULL, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
-- 
2.26.0

[PATCHv3 34/50] sparc: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/sparc/kernel/process_32.c | 17 ++++++++++++-----
 arch/sparc/kernel/traps_64.c   | 15 +++++++++++----
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 26cca65e9246..0b07de5618e5 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -145,10 +145,12 @@ void show_regs(struct pt_regs *r)
 }
 
 /*
- * The show_stack is an external API which we do not use ourselves.
+ * The show_stack(), show_stack_loglvl() are external APIs which
+ * we do not use ourselves.
  * The oops is printed in die_if_kernel.
  */
-void show_stack(struct task_struct *tsk, unsigned long *_ksp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
+		       const char *loglvl)
 {
 	unsigned long pc, fp;
 	unsigned long task_base;
@@ -170,11 +172,16 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 			break;
 		rw = (struct reg_window32 *) fp;
 		pc = rw->ins[7];
-		printk("[%08lx : ", pc);
-		printk("%pS ] ", (void *) pc);
+		printk("%s[%08lx : ", loglvl, pc);
+		printk("%s%pS ] ", loglvl, (void *) pc);
 		fp = rw->ins[6];
 	} while (++count < 16);
-	printk("\n");
+	printk("%s\n", loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
 
 /*
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 27778b65a965..8715bc93bd9d 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -18,6 +18,7 @@
 #include <linux/smp.h>
 #include <linux/mm.h>
 #include <linux/init.h>
+#include <linux/kallsyms.h>
 #include <linux/kdebug.h>
 #include <linux/ftrace.h>
 #include <linux/reboot.h>
@@ -2452,7 +2453,8 @@ static void user_instruction_dump(unsigned int __user *pc)
 	printk("\n");
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *_ksp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
+			 const char *loglvl)
 {
 	unsigned long fp, ksp;
 	struct thread_info *tp;
@@ -2476,7 +2478,7 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 
 	fp = ksp + STACK_BIAS;
 
-	printk("Call Trace:\n");
+	printk("%sCall Trace:\n", loglvl);
 	do {
 		struct sparc_stackf *sf;
 		struct pt_regs *regs;
@@ -2497,14 +2499,14 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 			fp = (unsigned long)sf->fp + STACK_BIAS;
 		}
 
-		printk(" [%016lx] %pS\n", pc, (void *) pc);
+		print_ip_sym(loglvl, pc);
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 		if ((pc + 8UL) == (unsigned long) &return_to_handler) {
 			struct ftrace_ret_stack *ret_stack;
 			ret_stack = ftrace_graph_get_ret_stack(tsk, graph);
 			if (ret_stack) {
 				pc = ret_stack->ret;
-				printk(" [%016lx] %pS\n", pc, (void *) pc);
+				print_ip_sym(loglvl, pc);
 				graph++;
 			}
 		}
@@ -2512,6 +2514,11 @@ void show_stack(struct task_struct *tsk, unsigned long *_ksp)
 	} while (++count < 16);
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *_ksp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
+}
+
 static inline struct reg_window *kernel_stack_up(struct reg_window *rw)
 {
 	unsigned long fp = rw->ins[6];
-- 
2.26.0

[PATCHv3 35/50] um/sysrq: Remove needless variable sp

[Dmitry Safonov]

`sp' is a needless excercise here.

Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: linux-um@lists.infradead.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/um/kernel/sysrq.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c
index c71b5ef7ea8c..c831a1c2eb94 100644
--- a/arch/um/kernel/sysrq.c
+++ b/arch/um/kernel/sysrq.c
@@ -27,7 +27,6 @@ static const struct stacktrace_ops stackops = {
 
 void show_stack(struct task_struct *task, unsigned long *stack)
 {
-	unsigned long *sp = stack;
 	struct pt_regs *segv_regs = current->thread.segv_regs;
 	int i;
 
@@ -38,10 +37,9 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	}
 
 	if (!stack)
-		sp = get_stack_pointer(task, segv_regs);
+		stack = get_stack_pointer(task, segv_regs);
 
 	pr_info("Stack:\n");
-	stack = sp;
 	for (i = 0; i < 3 * STACKSLOTS_PER_LINE; i++) {
 		if (kstack_end(stack))
 			break;
-- 
2.26.0

[PATCHv3 36/50] um: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: linux-um@lists.infradead.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/um/kernel/sysrq.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c
index c831a1c2eb94..1b54b6431499 100644
--- a/arch/um/kernel/sysrq.c
+++ b/arch/um/kernel/sysrq.c
@@ -17,7 +17,9 @@
 
 static void _print_addr(void *data, unsigned long address, int reliable)
 {
-	pr_info(" [<%08lx>] %s%pS\n", address, reliable ? "" : "? ",
+	const char *loglvl = data;
+
+	printk("%s [<%08lx>] %s%pS\n", loglvl, address, reliable ? "" : "? ",
 		(void *)address);
 }
 
@@ -25,7 +27,8 @@ static const struct stacktrace_ops stackops = {
 	.address = _print_addr
 };
 
-void show_stack(struct task_struct *task, unsigned long *stack)
+void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+		       const char *loglvl)
 {
 	struct pt_regs *segv_regs = current->thread.segv_regs;
 	int i;
@@ -39,17 +42,22 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 	if (!stack)
 		stack = get_stack_pointer(task, segv_regs);
 
-	pr_info("Stack:\n");
+	printk("%sStack:\n", loglvl);
 	for (i = 0; i < 3 * STACKSLOTS_PER_LINE; i++) {
 		if (kstack_end(stack))
 			break;
 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
-			pr_cont("\n");
+			printk("%s\n", loglvl);
 		pr_cont(" %08lx", *stack++);
 	}
-	pr_cont("\n");
+	printk("%s\n", loglvl);
+
+	printk("%sCall Trace:\n", loglvl);
+	dump_trace(current, &stackops, (void *)loglvl);
+	printk("%s\n", loglvl);
+}
 
-	pr_info("Call Trace:\n");
-	dump_trace(current, &stackops, NULL);
-	pr_info("\n");
+void show_stack(struct task_struct *task, unsigned long *stack)
+{
+	show_stack_loglvl(task, stack, KERN_INFO);
 }
-- 
2.26.0

[PATCHv3 37/50] unicore32: Remove unused pmode argument in c_backtrace()

[Dmitry Safonov]

The pmode parameter isn't used in assembly - remove it.
Second argument will be reused for printk() log level.

Cc: Guan Xuetao <gxt@pku.edu.cn>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/unicore32/kernel/setup.h |  2 +-
 arch/unicore32/kernel/traps.c | 14 +++++---------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/arch/unicore32/kernel/setup.h b/arch/unicore32/kernel/setup.h
index e40d3603c7e7..03e70e37f472 100644
--- a/arch/unicore32/kernel/setup.h
+++ b/arch/unicore32/kernel/setup.h
@@ -29,7 +29,7 @@ extern void kernel_thread_helper(void);
 extern void __init early_signal_init(void);
 
 extern asmlinkage void __backtrace(void);
-extern asmlinkage void c_backtrace(unsigned long fp, int pmode);
+extern asmlinkage void c_backtrace(unsigned long fp);
 
 extern void __show_regs(struct pt_regs *);
 
diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index e24f67283864..3682a4c5d927 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/arch/unicore32/kernel/traps.c
@@ -137,7 +137,7 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 
 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 {
-	unsigned int fp, mode;
+	unsigned int fp;
 	int ok = 1;
 
 	printk(KERN_DEFAULT "Backtrace: ");
@@ -145,16 +145,12 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	if (!tsk)
 		tsk = current;
 
-	if (regs) {
+	if (regs)
 		fp = regs->UCreg_fp;
-		mode = processor_mode(regs);
-	} else if (tsk != current) {
+	else if (tsk != current)
 		fp = thread_saved_fp(tsk);
-		mode = 0x10;
-	} else {
+	else
 		asm("mov %0, fp" : "=r" (fp) : : "cc");
-		mode = 0x10;
-	}
 
 	if (!fp) {
 		printk("no frame pointer");
@@ -167,7 +163,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	printk("\n");
 
 	if (ok)
-		c_backtrace(fp, mode);
+		c_backtrace(fp);
 }
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)
-- 
2.26.0

[PATCHv3 38/50] unicore32: Add loglvl to c_backtrace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level parameter to c_backtrace() as a preparation for
introducing show_stack_loglvl()

Cc: Guan Xuetao <gxt@pku.edu.cn>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/unicore32/kernel/setup.h  |  2 +-
 arch/unicore32/kernel/traps.c  |  2 +-
 arch/unicore32/lib/backtrace.S | 24 ++++++++++++++++--------
 3 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/arch/unicore32/kernel/setup.h b/arch/unicore32/kernel/setup.h
index 03e70e37f472..967352323185 100644
--- a/arch/unicore32/kernel/setup.h
+++ b/arch/unicore32/kernel/setup.h
@@ -29,7 +29,7 @@ extern void kernel_thread_helper(void);
 extern void __init early_signal_init(void);
 
 extern asmlinkage void __backtrace(void);
-extern asmlinkage void c_backtrace(unsigned long fp);
+extern asmlinkage void c_backtrace(unsigned long fp, const char *loglvl);
 
 extern void __show_regs(struct pt_regs *);
 
diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index 3682a4c5d927..2b7d73456865 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/arch/unicore32/kernel/traps.c
@@ -163,7 +163,7 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 	printk("\n");
 
 	if (ok)
-		c_backtrace(fp);
+		c_backtrace(fp, KERN_DEFAULT);
 }
 
 void show_stack(struct task_struct *tsk, unsigned long *sp)
diff --git a/arch/unicore32/lib/backtrace.S b/arch/unicore32/lib/backtrace.S
index f303671e2a4e..6221944b81f3 100644
--- a/arch/unicore32/lib/backtrace.S
+++ b/arch/unicore32/lib/backtrace.S
@@ -16,6 +16,7 @@
 #define sv_fp	v5
 #define sv_pc	v6
 #define offset	v8
+#define loglvl	v9
 
 ENTRY(__backtrace)
 		mov	r0, fp
@@ -27,10 +28,11 @@ ENTRY(c_backtrace)
 ENDPROC(__backtrace)
 ENDPROC(c_backtrace)
 #else
-		stm.w	(v4 - v8, lr), [sp-]	@ Save an extra register
+		stm.w	(v4 - v10, lr), [sp-]	@ Save an extra register
 						@ so we have a location...
 		mov.a	frame, r0		@ if frame pointer is zero
 		beq	no_frame		@ we have no stack frames
+		mov	loglvl, r1
 
 1:		stm.w	(pc), [sp-]		@ calculate offset of PC stored
 		ldw.w	r0, [sp]+, #4		@ by stmfd for this CPU
@@ -95,9 +97,10 @@ for_each_frame:
 		bua	for_each_frame
 
 1006:		adr	r0, .Lbad
-		mov	r1, frame
+		mov	r1, loglvl
+		mov	r2, frame
 		b.l	printk
-no_frame:	ldm.w	(v4 - v8, pc), [sp]+
+no_frame:	ldm.w	(v4 - v10, pc), [sp]+
 ENDPROC(__backtrace)
 ENDPROC(c_backtrace)
 
@@ -128,8 +131,11 @@ ENDPROC(c_backtrace)
 		add	v7, v7, #1
 		cxor.a	v7, #6
 		cmoveq	v7, #1
-		cmoveq	r1, #'\n'
-		cmovne	r1, #' '
+		bne	201f
+		adr	r0, .Lcr
+		mov	r1, loglvl
+		b.l	printk
+201:
 		ldw.w	r3, [stack]+, #-4
 		mov	r2, reg
 		csub.a	r2, #8
@@ -141,18 +147,20 @@ ENDPROC(c_backtrace)
 		add	r2, r2, #0x10		@ so r2 need add 16
 201:
 		adr	r0, .Lfp
+		mov	r1, loglvl
 		b.l	printk
 2:		sub.a	reg, reg, #1
 		bns	1b
 		cxor.a	v7, #0
 		beq	201f
 		adr	r0, .Lcr
+		mov	r1, loglvl
 		b.l	printk
 201:		ldm.w	(instr, reg, stack, v7, pc), [sp]+
 
-.Lfp:		.asciz	"%cr%d:%08x"
-.Lcr:		.asciz	"\n"
-.Lbad:		.asciz	"Backtrace aborted due to bad frame pointer <%p>\n"
+.Lfp:		.asciz	"%sr%d:%08x "
+.Lcr:		.asciz	"%s\n"
+.Lbad:		.asciz	"%sBacktrace aborted due to bad frame pointer <%p>\n"
 		.align
 .Ldsi:		.word	0x92eec000 >> 14	@ stm.w sp, (... fp, ip, lr, pc)
 		.word	0x92e10000 >> 14	@ stm.w sp, ()
-- 
2.26.0

[PATCHv3 39/50] unicore32: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

As a nice side-effect - print backtrace in __die() with the same log
level as the rest of function.

Cc: Guan Xuetao <gxt@pku.edu.cn>
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/unicore32/kernel/traps.c | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index 2b7d73456865..8b1335997f50 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/arch/unicore32/kernel/traps.c
@@ -135,12 +135,13 @@ static void dump_instr(const char *lvl, struct pt_regs *regs)
 	set_fs(fs);
 }
 
-static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
+static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
+			   const char *loglvl)
 {
 	unsigned int fp;
 	int ok = 1;
 
-	printk(KERN_DEFAULT "Backtrace: ");
+	printk("%sBacktrace: ", loglvl);
 
 	if (!tsk)
 		tsk = current;
@@ -153,25 +154,31 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
 		asm("mov %0, fp" : "=r" (fp) : : "cc");
 
 	if (!fp) {
-		printk("no frame pointer");
+		printk("%sno frame pointer", loglvl);
 		ok = 0;
 	} else if (verify_stack(fp)) {
-		printk("invalid frame pointer 0x%08x", fp);
+		printk("%sinvalid frame pointer 0x%08x", loglvl, fp);
 		ok = 0;
 	} else if (fp < (unsigned long)end_of_stack(tsk))
-		printk("frame pointer underflow");
-	printk("\n");
+		printk("%sframe pointer underflow", loglvl);
+	printk("%s\n", loglvl);
 
 	if (ok)
-		c_backtrace(fp, KERN_DEFAULT);
+		c_backtrace(fp, loglvl);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+		       const char *loglvl)
 {
-	dump_backtrace(NULL, tsk);
+	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
+void show_stack(struct task_struct *tsk, unsigned long *sp)
+{
+	show_stack_loglvl(tsk, sp, KERN_DEFAULT)
+}
+
 static int __die(const char *str, int err, struct thread_info *thread,
 		struct pt_regs *regs)
 {
@@ -196,7 +203,7 @@ static int __die(const char *str, int err, struct thread_info *thread,
 	if (!user_mode(regs) || in_interrupt()) {
 		dump_mem(KERN_EMERG, "Stack: ", regs->UCreg_sp,
 			 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
-		dump_backtrace(regs, tsk);
+		dump_backtrace(regs, tsk, KERN_EMERG);
 		dump_instr(KERN_EMERG, regs);
 	}
 
-- 
2.26.0

[PATCHv3 40/50] x86: Add missing const qualifiers for log_lvl

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Keep log_lvl const show_trace_log_lvl() and printk_stack_address()
as the new generic show_stack_loglvl() wants to have a proper const
qualifier.

And gcc rightfully produces warnings in case it's not keept:
arch/x86/kernel/dumpstack.c: In function ‘show_stack’:
arch/x86/kernel/dumpstack.c:294:37: warning: passing argument 4 of ‘show_trace_log_lv ’ discards ‘const’ qualifier from pointer target type [-Wdiscarded-qualifiers]
  294 |  show_trace_log_lvl(task, NULL, sp, loglvl);
      |                                     ^~~~~~
arch/x86/kernel/dumpstack.c:163:32: note: expected ‘char *’ but argument is of type ‘const char *’
  163 |    unsigned long *stack, char *log_lvl)
      |                          ~~~~~~^~~~~~~

Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/x86/include/asm/stacktrace.h | 2 +-
 arch/x86/kernel/dumpstack.c       | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h
index 14db05086bbf..5ae5a68e469d 100644
--- a/arch/x86/include/asm/stacktrace.h
+++ b/arch/x86/include/asm/stacktrace.h
@@ -87,7 +87,7 @@ get_stack_pointer(struct task_struct *task, struct pt_regs *regs)
 }
 
 void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
-			unsigned long *stack, char *log_lvl);
+			unsigned long *stack, const char *log_lvl);
 
 /* The form of the top of the frame on the stack */
 struct stack_frame {
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index ae64ec7f752f..b94bc31a1757 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -65,7 +65,7 @@ bool in_entry_stack(unsigned long *stack, struct stack_info *info)
 }
 
 static void printk_stack_address(unsigned long address, int reliable,
-				 char *log_lvl)
+				 const char *log_lvl)
 {
 	touch_nmi_watchdog();
 	printk("%s %s%pB\n", log_lvl, reliable ? "" : "? ", (void *)address);
@@ -160,7 +160,7 @@ static void show_regs_if_on_stack(struct stack_info *info, struct pt_regs *regs,
 }
 
 void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
-			unsigned long *stack, char *log_lvl)
+			unsigned long *stack, const char *log_lvl)
 {
 	struct unwind_state state;
 	struct stack_info stack_info = {0};
-- 
2.26.0

[PATCHv3 41/50] x86: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/x86/kernel/dumpstack.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index b94bc31a1757..4396f2cfad19 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -279,7 +279,8 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	}
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	task = task ? : current;
 
@@ -290,7 +291,12 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	if (!sp && task == current)
 		sp = get_stack_pointer(current, NULL);
 
-	show_trace_log_lvl(task, NULL, sp, KERN_DEFAULT);
+	show_trace_log_lvl(task, NULL, sp, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_DEFAULT);
 }
 
 void show_stack_regs(struct pt_regs *regs)
-- 
2.26.0

[PATCHv3 42/50] xtensa: Add loglvl to show_trace()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Add log level argument to show_trace() as a preparation for introducing
show_stack_loglvl().

Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/xtensa/kernel/traps.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 0976e27b8d5d..c397a02457bc 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -479,18 +479,22 @@ void show_regs(struct pt_regs * regs)
 
 static int show_trace_cb(struct stackframe *frame, void *data)
 {
+	const char *loglvl = data;
+
 	if (kernel_text_address(frame->pc))
-		pr_cont(" [<%08lx>] %pB\n", frame->pc, (void *)frame->pc);
+		printk("%s [<%08lx>] %pB\n",
+			loglvl, frame->pc, (void *)frame->pc);
 	return 0;
 }
 
-void show_trace(struct task_struct *task, unsigned long *sp)
+static void show_trace(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	if (!sp)
 		sp = stack_pointer(task);
 
-	pr_info("Call Trace:\n");
-	walk_stackframe(sp, show_trace_cb, NULL);
+	printk("%sCall Trace:\n", loglvl);
+	walk_stackframe(sp, show_trace_cb, (void *)loglvl);
 }
 
 #define STACK_DUMP_ENTRY_SIZE 4
@@ -511,7 +515,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
 		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
 		       sp, len, false);
-	show_trace(task, sp);
+	show_trace(task, stack, KERN_INFO);
 }
 
 DEFINE_SPINLOCK(die_lock);
-- 
2.26.0

Re: [PATCHv3 42/50] xtensa: Add loglvl to show_trace()

[Mike Rapoport]

Hi,

On Sat, Apr 18, 2020 at 09:19:36PM +0100, Dmitry Safonov wrote:
> Currently, the log-level of show_stack() depends on a platform
> realization. It creates situations where the headers are printed with
> lower log level or higher than the stacktrace (depending on
> a platform or user).
> 
> Furthermore, it forces the logic decision from user to an architecture
> side. In result, some users as sysrq/kdb/etc are doing tricks with
> temporary rising console_loglevel while printing their messages.
> And in result it not only may print unwanted messages from other CPUs,
> but also omit printing at all in the unlucky case where the printk()
> was deferred.
> 
> Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
> an easier approach than introducing more printk buffers.
> Also, it will consolidate printings with headers.
> 
> Add log level argument to show_trace() as a preparation for introducing
> show_stack_loglvl().
> 
> Cc: Chris Zankel <chris@zankel.net>
> Cc: Max Filippov <jcmvbkbc@gmail.com>
> Cc: linux-xtensa@linux-xtensa.org
> [1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
> Signed-off-by: Dmitry Safonov <dima@arista.com>
> ---
>  arch/xtensa/kernel/traps.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
> index 0976e27b8d5d..c397a02457bc 100644
> --- a/arch/xtensa/kernel/traps.c
> +++ b/arch/xtensa/kernel/traps.c
> -void show_trace(struct task_struct *task, unsigned long *sp)
> +static void show_trace(struct task_struct *task, unsigned long *sp,
> +		       const char *loglvl)
>  {
>  	if (!sp)
>  		sp = stack_pointer(task);
>  
> -	pr_info("Call Trace:\n");
> -	walk_stackframe(sp, show_trace_cb, NULL);
> +	printk("%sCall Trace:\n", loglvl);
> +	walk_stackframe(sp, show_trace_cb, (void *)loglvl);
>  }
>  
>  #define STACK_DUMP_ENTRY_SIZE 4
> @@ -511,7 +515,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
>  	print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
>  		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
>  		       sp, len, false);
> -	show_trace(task, sp);
> +	show_trace(task, stack, KERN_INFO);

it should have been

	show_trace(task, sp, KERN_INFO);

Andrew, can you fold the following patch as a fixup please:


diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index f9217b6b45c8..efc3a29cde80 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -515,7 +515,7 @@ void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
 	print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE,
 		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
 		       sp, len, false);
-	show_trace(task, stack, loglvl);
+	show_trace(task, sp, loglvl);
 }
 
 DEFINE_SPINLOCK(die_lock);
-- 
2.26.1


-- 
2.26.1


>  }
>  
>  DEFINE_SPINLOCK(die_lock);
> -- 
> 2.26.0
> 

-- 
Sincerely yours,
Mike.

Re: [PATCHv3 42/50] xtensa: Add loglvl to show_trace()

[Dmitry Safonov]

Hi Mike,

On 5/11/20 8:45 PM, Mike Rapoport wrote:
[..]
>> @@ -511,7 +515,7 @@ void show_stack(struct task_struct *task, unsigned long *sp)
>>  	print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
>>  		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
>>  		       sp, len, false);
>> -	show_trace(task, sp);
>> +	show_trace(task, stack, KERN_INFO);
> 
> it should have been
> 
> 	show_trace(task, sp, KERN_INFO);

Thank you for noticing it!

> 
> Andrew, can you fold the following patch as a fixup please:
> 
> 
> diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
> index f9217b6b45c8..efc3a29cde80 100644
> --- a/arch/xtensa/kernel/traps.c
> +++ b/arch/xtensa/kernel/traps.c
> @@ -515,7 +515,7 @@ void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
>  	print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE,
>  		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
>  		       sp, len, false);
> -	show_trace(task, stack, loglvl);
> +	show_trace(task, sp, loglvl);
>  }
>  
>  DEFINE_SPINLOCK(die_lock);
> 

Thanks,
          Dmitry

[PATCHv3 43/50] xtensa: Add show_stack_loglvl()

[Dmitry Safonov]

Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on
a platform or user).

Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages.
And in result it not only may print unwanted messages from other CPUs,
but also omit printing at all in the unlucky case where the printk()
was deferred.

Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems
an easier approach than introducing more printk buffers.
Also, it will consolidate printings with headers.

Introduce show_stack_loglvl(), that eventually will substitute
show_stack().

Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/xtensa/kernel/traps.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index c397a02457bc..3a50813eeb70 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -501,7 +501,8 @@ static void show_trace(struct task_struct *task, unsigned long *sp,
 #define STACK_DUMP_LINE_SIZE 32
 static size_t kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack(struct task_struct *task, unsigned long *sp)
+void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl)
 {
 	size_t len;
 
@@ -511,11 +512,16 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 	len = min((-(size_t)sp) & (THREAD_SIZE - STACK_DUMP_ENTRY_SIZE),
 		  kstack_depth_to_print * STACK_DUMP_ENTRY_SIZE);
 
-	pr_info("Stack:\n");
-	print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
+	printk("%sStack:\n", loglvl);
+	print_hex_dump(loglvl, " ", DUMP_PREFIX_NONE,
 		       STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
 		       sp, len, false);
-	show_trace(task, stack, KERN_INFO);
+	show_trace(task, stack, loglvl);
+}
+
+void show_stack(struct task_struct *task, unsigned long *sp)
+{
+	show_stack_loglvl(task, sp, KERN_INFO);
 }
 
 DEFINE_SPINLOCK(die_lock);
-- 
2.26.0

[PATCHv3 44/50] sysrq: Use show_stack_loglvl()

[Dmitry Safonov]

Show the stack trace on a CPU with the same log level as "CPU%d" header.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 drivers/tty/sysrq.c         | 2 +-
 include/linux/sched/debug.h | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index 5e0d0813da55..b11300b16f62 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -232,7 +232,7 @@ static void showacpu(void *dummy)
 
 	raw_spin_lock_irqsave(&show_lock, flags);
 	pr_info("CPU%d:\n", smp_processor_id());
-	show_stack(NULL, NULL);
+	show_stack_loglvl(NULL, NULL, KERN_INFO);
 	raw_spin_unlock_irqrestore(&show_lock, flags);
 }
 
diff --git a/include/linux/sched/debug.h b/include/linux/sched/debug.h
index 95fb9e025247..373e4e3faf2a 100644
--- a/include/linux/sched/debug.h
+++ b/include/linux/sched/debug.h
@@ -31,6 +31,8 @@ extern void show_regs(struct pt_regs *);
  * trace (or NULL if the entire call-chain of the task should be shown).
  */
 extern void show_stack(struct task_struct *task, unsigned long *sp);
+extern void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+			      const char *loglvl);
 
 extern void sched_show_task(struct task_struct *p);
 
-- 
2.26.0

[PATCHv3 45/50] x86/amd_gart: Print stacktrace for a leak with KERN_ERR

[Dmitry Safonov]

It's under CONFIG_IOMMU_LEAK option which is enabled by debug config.
Likely the backtrace is worth to be seen - so aligning with log level of
error message in iommu_full().

Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/x86/kernel/amd_gart_64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 16133819415c..9d2c076be37a 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -159,7 +159,7 @@ static void dump_leak(void)
 		return;
 	dump = 1;
 
-	show_stack(NULL, NULL);
+	show_stack_loglvl(NULL, NULL, KERN_ERR);
 	debug_dma_dump_mappings(NULL);
 }
 #endif
-- 
2.26.0

[PATCHv3 46/50] power: Use show_stack_loglvl()

[Dmitry Safonov]

Aligning with other watchdog messages just before panic - use
KERN_EMERG.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 drivers/base/power/main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index fdd508a78ffd..fc0108e65592 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -519,7 +519,7 @@ static void dpm_watchdog_handler(struct timer_list *t)
 	struct dpm_watchdog *wd = from_timer(wd, t, timer);
 
 	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
-	show_stack(wd->tsk, NULL);
+	show_stack_loglvl(wd->tsk, NULL, KERN_EMERG);
 	panic("%s %s: unrecoverable failure\n",
 		dev_driver_string(wd->dev), dev_name(wd->dev));
 }
-- 
2.26.0

[PATCHv3 47/50] kdb: Don't play with console_loglevel

[Dmitry Safonov]

Print the stack trace with KERN_EMERG - it should be always visible.

Playing with console_loglevel is a bad idea as there may be more
messages printed than wanted. Also the stack trace might be not printed
at all if printk() was deferred and console_loglevel was raised back
before the trace got flushed.

Unfortunately, after rebasing on commit 2277b492582d ("kdb: Fix stack
crawling on 'running' CPUs that aren't the master"), kdb_show_stack()
uses now kdb_dump_stack_on_cpu(), which for now won't be converted as it
uses dump_stack() instead of show_stack().

Convert for now the branch that uses show_stack() and remove
console_loglevel exercise from that case.

Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Douglas Anderson <dianders@chromium.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: kgdb-bugreport@lists.sourceforge.net
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 kernel/debug/kdb/kdb_bt.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 3de0cc780c16..43f5dcd2b9ac 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -21,17 +21,18 @@
 
 static void kdb_show_stack(struct task_struct *p, void *addr)
 {
-	int old_lvl = console_loglevel;
-
-	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 	kdb_trap_printk++;
 
-	if (!addr && kdb_task_has_cpu(p))
+	if (!addr && kdb_task_has_cpu(p)) {
+		int old_lvl = console_loglevel;
+
+		console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 		kdb_dump_stack_on_cpu(kdb_process_cpu(p));
-	else
-		show_stack(p, addr);
+		console_loglevel = old_lvl;
+	} else {
+		show_stack_loglvl(p, addr, KERN_EMERG);
+	}
 
-	console_loglevel = old_lvl;
 	kdb_trap_printk--;
 }
 
-- 
2.26.0

[PATCHv3 48/50] sched: Print stack trace with KERN_INFO

[Dmitry Safonov]

Aligning with other messages printed in sched_show_task() - use
KERN_INFO to print the backtrace.

Cc: Ben Segall <bsegall@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 kernel/sched/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e6ea7c17a362..581a219ac062 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5957,7 +5957,7 @@ void sched_show_task(struct task_struct *p)
 		(unsigned long)task_thread_info(p)->flags);
 
 	print_worker_info(KERN_INFO, p);
-	show_stack(p, NULL);
+	show_stack_loglvl(p, NULL, KERN_INFO);
 	put_task_stack(p);
 }
 EXPORT_SYMBOL_GPL(sched_show_task);
-- 
2.26.0

[PATCHv3 49/50] kernel: Use show_stack_loglvl()

[Dmitry Safonov]

Align the last users of show_stack() by KERN_DEFAULT as the surrounding
headers/messages.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 kernel/locking/rtmutex-debug.c | 2 +-
 lib/dump_stack.c               | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
index fd4fe1f5b458..5e63d6e8a223 100644
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -125,7 +125,7 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
 
 	printk("\n%s/%d's [blocked] stackdump:\n\n",
 		task->comm, task_pid_nr(task));
-	show_stack(task, NULL);
+	show_stack_loglvl(task, NULL, KERN_DEFAULT);
 	printk("\n%s/%d's [current] stackdump:\n\n",
 		current->comm, task_pid_nr(current));
 	dump_stack();
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 33ffbf308853..5595e8962cf6 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -74,7 +74,7 @@ void show_regs_print_info(const char *log_lvl)
 static void __dump_stack(void)
 {
 	dump_stack_print_info(KERN_DEFAULT);
-	show_stack(NULL, NULL);
+	show_stack_loglvl(NULL, NULL, KERN_DEFAULT);
 }
 
 /**
-- 
2.26.0

[PATCHv3 50/50] kernel: Rename show_stack_loglvl() => show_stack()

[Dmitry Safonov]

Now the last users of show_stack() got converted to use an explicit log
level, show_stack_loglvl() can drop it's redundant suffix and become
once again well known show_stack().

Signed-off-by: Dmitry Safonov <dima@arista.com>
---
 arch/alpha/kernel/traps.c        |  8 +-------
 arch/arc/kernel/stacktrace.c     |  8 +-------
 arch/arm/kernel/traps.c          |  8 +-------
 arch/arm64/kernel/traps.c        |  8 +-------
 arch/c6x/kernel/traps.c          |  7 +------
 arch/csky/kernel/dumpstack.c     |  7 +------
 arch/csky/kernel/ptrace.c        |  4 ++--
 arch/h8300/kernel/traps.c        |  8 +-------
 arch/hexagon/kernel/traps.c      |  8 +-------
 arch/ia64/kernel/mca.c           |  2 +-
 arch/ia64/kernel/process.c       | 11 ++---------
 arch/m68k/kernel/traps.c         | 11 +++--------
 arch/microblaze/kernel/traps.c   |  8 +-------
 arch/mips/kernel/traps.c         |  8 +-------
 arch/nds32/kernel/traps.c        |  8 +-------
 arch/nios2/kernel/traps.c        | 12 +++---------
 arch/openrisc/kernel/traps.c     | 10 ++--------
 arch/parisc/kernel/traps.c       |  8 +-------
 arch/powerpc/kernel/process.c    | 11 +++--------
 arch/powerpc/kernel/stacktrace.c |  2 +-
 arch/riscv/kernel/stacktrace.c   |  8 +-------
 arch/s390/kernel/dumpstack.c     |  9 ++-------
 arch/sh/kernel/dumpstack.c       |  8 +-------
 arch/sh/kernel/process_64.c      |  3 +--
 arch/sparc/kernel/process_32.c   | 11 ++---------
 arch/sparc/kernel/process_64.c   |  2 +-
 arch/sparc/kernel/traps_64.c     |  8 +-------
 arch/um/drivers/mconsole_kern.c  |  2 +-
 arch/um/kernel/sysrq.c           |  7 +------
 arch/unicore32/kernel/traps.c    |  7 +------
 arch/x86/kernel/amd_gart_64.c    |  2 +-
 arch/x86/kernel/dumpstack.c      |  7 +------
 arch/xtensa/kernel/traps.c       | 10 ++--------
 drivers/base/power/main.c        |  2 +-
 drivers/tty/sysrq.c              |  2 +-
 include/linux/sched/debug.h      |  5 ++---
 kernel/debug/kdb/kdb_bt.c        |  2 +-
 kernel/locking/rtmutex-debug.c   |  2 +-
 kernel/sched/core.c              |  2 +-
 lib/dump_stack.c                 |  2 +-
 40 files changed, 53 insertions(+), 205 deletions(-)

diff --git a/arch/alpha/kernel/traps.c b/arch/alpha/kernel/traps.c
index 2402f1777f54..8383ccfaccdc 100644
--- a/arch/alpha/kernel/traps.c
+++ b/arch/alpha/kernel/traps.c
@@ -144,8 +144,7 @@ dik_show_trace(unsigned long *sp, const char *loglvl)
 
 static int kstack_depth_to_print = 24;
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
-			const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
 {
 	unsigned long *stack;
 	int i;
@@ -174,11 +173,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
 	dik_show_trace(sp, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
-
 void
 die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
 {
diff --git a/arch/arc/kernel/stacktrace.c b/arch/arc/kernel/stacktrace.c
index 24f9cd8a12c9..feba91c9d969 100644
--- a/arch/arc/kernel/stacktrace.c
+++ b/arch/arc/kernel/stacktrace.c
@@ -228,17 +228,11 @@ noinline void show_stacktrace(struct task_struct *tsk, struct pt_regs *regs,
 EXPORT_SYMBOL(show_stacktrace);
 
 /* Expected by sched Code */
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
-			const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
 {
 	show_stacktrace(tsk, NULL, loglvl);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
-{
-	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
-}
-
 /* Another API expected by schedular, shows up in "ps" as Wait Channel
  * Of course just returning schedule( ) would be pointless so unwind until
  * the function is not in schedular code
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 00455b5bbf8a..09faa0efe47b 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -247,18 +247,12 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 }
 #endif
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
 {
 	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
-{
-	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
-}
-
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #elif defined(CONFIG_PREEMPT_RT)
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 516e92332fd0..4857e9d60359 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -137,18 +137,12 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 	put_task_stack(tsk);
 }
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
 {
 	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
-{
-	show_stack_loglvl(tsk, sp, KERN_DEFAULT);
-}
-
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
 #elif defined(CONFIG_PREEMPT_RT)
diff --git a/arch/c6x/kernel/traps.c b/arch/c6x/kernel/traps.c
index 4afbf48f1ce0..2b9121c755be 100644
--- a/arch/c6x/kernel/traps.c
+++ b/arch/c6x/kernel/traps.c
@@ -374,7 +374,7 @@ static void show_trace(unsigned long *stack, unsigned long *endstack,
 	printk("%s\n", loglvl);
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+void show_stack(struct task_struct *task, unsigned long *stack,
 		const char *loglvl)
 {
 	unsigned long *p, *endstack;
@@ -403,11 +403,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
 	show_trace(stack, endstack, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	show_stack_loglvl(task, stack, KERN_DEBUG);
-}
-
 int is_valid_bugaddr(unsigned long addr)
 {
 	return __kernel_text_address(addr);
diff --git a/arch/csky/kernel/dumpstack.c b/arch/csky/kernel/dumpstack.c
index c500837390d3..b9660b1944a1 100644
--- a/arch/csky/kernel/dumpstack.c
+++ b/arch/csky/kernel/dumpstack.c
@@ -32,7 +32,7 @@ static void show_trace(unsigned long *stack, const char *loglvl)
 	pr_cont("\n");
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+void show_stack(struct task_struct *task, unsigned long *stack,
 		const char *loglvl)
 {
 	if (!stack) {
@@ -48,8 +48,3 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
 
 	show_trace(stack, loglvl);
 }
-
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	show_stack_loglvl(task, stack, KERN_INFO);
-}
diff --git a/arch/csky/kernel/ptrace.c b/arch/csky/kernel/ptrace.c
index 21ac2608f205..ffd8a85d1596 100644
--- a/arch/csky/kernel/ptrace.c
+++ b/arch/csky/kernel/ptrace.c
@@ -338,7 +338,7 @@ asmlinkage void syscall_trace_exit(struct pt_regs *regs)
 		trace_sys_exit(regs, syscall_get_return_value(current, regs));
 }
 
-extern void show_stack(struct task_struct *task, unsigned long *stack);
+extern void show_stack(struct task_struct *task, unsigned long *stack, const char *loglvl);
 void show_regs(struct pt_regs *fp)
 {
 	unsigned long   *sp;
@@ -414,6 +414,6 @@ void show_regs(struct pt_regs *fp)
 	}
 	pr_cont("\n");
 
-	show_stack(NULL, (unsigned long *)fp->regs[4]);
+	show_stack(NULL, (unsigned long *)fp->regs[4], KERN_INFO);
 	return;
 }
diff --git a/arch/h8300/kernel/traps.c b/arch/h8300/kernel/traps.c
index 6362446563d6..5d8b969cd8f3 100644
--- a/arch/h8300/kernel/traps.c
+++ b/arch/h8300/kernel/traps.c
@@ -115,8 +115,7 @@ void die(const char *str, struct pt_regs *fp, unsigned long err)
 
 static int kstack_depth_to_print = 24;
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *esp, const char *loglvl)
 {
 	unsigned long *stack,  addr;
 	int i;
@@ -158,8 +157,3 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
 	}
 	printk("%s\n", loglvl);
 }
-
-void show_stack(struct task_struct *task, unsigned long *esp)
-{
-	show_stack_loglvl(task, esp, KERN_INFO);
-}
diff --git a/arch/hexagon/kernel/traps.c b/arch/hexagon/kernel/traps.c
index a8a3a210d781..904134b37232 100644
--- a/arch/hexagon/kernel/traps.c
+++ b/arch/hexagon/kernel/traps.c
@@ -175,18 +175,12 @@ static void do_show_stack(struct task_struct *task, unsigned long *fp,
 	}
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *fp,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *fp, const char *loglvl)
 {
 	/* Saved link reg is one word above FP */
 	do_show_stack(task, fp, 0, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *fp)
-{
-	show_stack_loglvl(task, fp, 0, KERN_INFO);
-}
-
 int die(const char *str, struct pt_regs *regs, long err)
 {
 	static struct {
diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 6fb54dfa1350..2703f7795672 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -1631,7 +1631,7 @@ default_monarch_init_process(struct notifier_block *self, unsigned long val, voi
 	if (read_trylock(&tasklist_lock)) {
 		do_each_thread (g, t) {
 			printk("\nBacktrace of pid %d (%s)\n", t->pid, t->comm);
-			show_stack(t, NULL);
+			show_stack(t, NULL, KERN_DEFAULT);
 		} while_each_thread (g, t);
 		read_unlock(&tasklist_lock);
 	}
diff --git a/arch/ia64/kernel/process.c b/arch/ia64/kernel/process.c
index 913d9a01cbf9..96dfb9e4b16f 100644
--- a/arch/ia64/kernel/process.c
+++ b/arch/ia64/kernel/process.c
@@ -85,8 +85,7 @@ ia64_do_show_stack (struct unw_frame_info *info, void *arg)
 }
 
 void
-show_stack_loglvl (struct task_struct *task, unsigned long *sp,
-		   const char *loglvl)
+show_stack (struct task_struct *task, unsigned long *sp, const char *loglvl)
 {
 	if (!task)
 		unw_init_running(ia64_do_show_stack, (void *)loglvl);
@@ -98,12 +97,6 @@ show_stack_loglvl (struct task_struct *task, unsigned long *sp,
 	}
 }
 
-void
-show_stack (struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
-
 void
 show_regs (struct pt_regs *regs)
 {
@@ -158,7 +151,7 @@ show_regs (struct pt_regs *regs)
 			       ((i == sof - 1) || (i % 3) == 2) ? "\n" : " ");
 		}
 	} else
-		show_stack(NULL, NULL);
+		show_stack(NULL, NULL, KERN_DEFAULT);
 }
 
 /* local support for deprecated console_print */
diff --git a/arch/m68k/kernel/traps.c b/arch/m68k/kernel/traps.c
index ffcc5ec4fac3..df6fc782754f 100644
--- a/arch/m68k/kernel/traps.c
+++ b/arch/m68k/kernel/traps.c
@@ -916,7 +916,7 @@ void show_registers(struct pt_regs *regs)
 	default:
 		pr_cont("\n");
 	}
-	show_stack(NULL, (unsigned long *)addr);
+	show_stack(NULL, (unsigned long *)addr, KERN_INFO);
 
 	pr_info("Code:");
 	set_fs(KERNEL_DS);
@@ -935,8 +935,8 @@ void show_registers(struct pt_regs *regs)
 	pr_cont("\n");
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
 {
 	unsigned long *p;
 	unsigned long *endstack;
@@ -963,11 +963,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
 	show_trace(stack, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	show_stack_loglvl(task, stack, KERN_INFO);
-}
-
 /*
  * The vector number returned in the frame pointer may also contain
  * the "fs" (Fault Status) bits on ColdFire. These are in the bottom
diff --git a/arch/microblaze/kernel/traps.c b/arch/microblaze/kernel/traps.c
index 149ae534937e..94b6fe93147d 100644
--- a/arch/microblaze/kernel/traps.c
+++ b/arch/microblaze/kernel/traps.c
@@ -31,8 +31,7 @@ static int __init kstack_setup(char *s)
 }
 __setup("kstack=", kstack_setup);
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
 {
 	unsigned long words_to_show;
 	u32 fp = (u32) sp;
@@ -77,8 +76,3 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
 
 	debug_show_held_locks(task);
 }
-
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_INFO);
-}
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 077aabbd6b9f..4522902228b5 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -196,8 +196,7 @@ static void show_stacktrace(struct task_struct *task,
 	show_backtrace(task, regs, loglvl);
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
 {
 	struct pt_regs regs;
 	mm_segment_t old_fs = get_fs();
@@ -225,11 +224,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
 	set_fs(old_fs);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT)
-}
-
 static void show_code(unsigned int __user *pc)
 {
 	long i;
diff --git a/arch/nds32/kernel/traps.c b/arch/nds32/kernel/traps.c
index 90f12582c218..6a9772ba7392 100644
--- a/arch/nds32/kernel/traps.c
+++ b/arch/nds32/kernel/traps.c
@@ -135,8 +135,7 @@ static void __dump(struct task_struct *tsk, unsigned long *base_reg,
 	printk("%s\n", loglvl);
 }
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
 {
 	unsigned long *base_reg;
 
@@ -157,11 +156,6 @@ void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
 	barrier();
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
-{
-	show_stack_loglvl(tsk, sp, KERN_EMERG);
-}
-
 DEFINE_SPINLOCK(die_lock);
 
 /*
diff --git a/arch/nios2/kernel/traps.c b/arch/nios2/kernel/traps.c
index 08071caa9b36..b172da4eb1a9 100644
--- a/arch/nios2/kernel/traps.c
+++ b/arch/nios2/kernel/traps.c
@@ -52,14 +52,13 @@ void _exception(int signo, struct pt_regs *regs, int code, unsigned long addr)
 }
 
 /*
- * The show_stack(), show_stack_loglvl() are external API
- * which we do not use ourselves.
+ * The show_stack() is external API which we do not use ourselves.
  */
 
 int kstack_depth_to_print = 48;
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *stack,
+		const char *loglvl)
 {
 	unsigned long *endstack, addr;
 	int i;
@@ -106,11 +105,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
 	printk("%s\n", loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	show_stack_loglvl(task, stack, KERN_EMERG);
-}
-
 void __init trap_init(void)
 {
 	/* Nothing to do here */
diff --git a/arch/openrisc/kernel/traps.c b/arch/openrisc/kernel/traps.c
index 3b7978a22d68..3022b0ad142c 100644
--- a/arch/openrisc/kernel/traps.c
+++ b/arch/openrisc/kernel/traps.c
@@ -48,8 +48,7 @@ void print_trace(void *data, unsigned long addr, int reliable)
 }
 
 /* displays a short stack trace */
-void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
-		const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *esp, const char *loglvl)
 {
 	if (esp == NULL)
 		esp = (unsigned long *)&esp;
@@ -58,11 +57,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *esp,
 	unwind_stack((void *)loglvl, esp, print_trace);
 }
 
-void show_stack(struct task_struct *task, unsigned long *esp)
-{
-	show_stack_loglvl(task, esp, KERN_EMERG);
-}
-
 void show_registers(struct pt_regs *regs)
 {
 	int i;
@@ -104,7 +98,7 @@ void show_registers(struct pt_regs *regs)
 	if (in_kernel) {
 
 		printk("\nStack: ");
-		show_stack(NULL, (unsigned long *)esp);
+		show_stack(NULL, (unsigned long *)esp, KERN_EMERG);
 
 		printk("\nCode: ");
 		if (regs->pc < PAGE_OFFSET)
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index c2411de3730f..0a89899f154a 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -198,17 +198,11 @@ static void parisc_show_stack(struct task_struct *task,
 	do_show_stack(&info, loglvl);
 }
 
-void show_stack_loglvl(struct task_struct *t, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *t, unsigned long *sp, const char *loglvl)
 {
 	parisc_show_stack(t, NULL, loglvl);
 }
 
-void show_stack(struct task_struct *t, unsigned long *sp)
-{
-	show_stack_loglvl(t, sp, KERN_CRIT)
-}
-
 int is_valid_bugaddr(unsigned long iaoq)
 {
 	return 1;
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 6ad438d59796..75cb6d8af164 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1444,7 +1444,7 @@ void show_regs(struct pt_regs * regs)
 	printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
 	printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
 #endif
-	show_stack(current, (unsigned long *) regs->gpr[1]);
+	show_stack(current, (unsigned long *) regs->gpr[1], KERN_DEFAULT);
 	if (!user_mode(regs))
 		show_instructions(regs);
 }
@@ -2068,8 +2068,8 @@ unsigned long get_wchan(struct task_struct *p)
 
 static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack,
-		       const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *stack,
+		const char *loglvl)
 {
 	unsigned long sp, ip, lr, newsp;
 	int count = 0;
@@ -2138,11 +2138,6 @@ void show_stack_loglvl(struct task_struct *tsk, unsigned long *stack,
 	put_task_stack(tsk);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *stack)
-{
-	show_stack_loglvl(tsk, stack, KERN_DEFAULT);
-}
-
 #ifdef CONFIG_PPC64
 /* Called with hard IRQs off */
 void notrace __ppc64_runlatch_on(void)
diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
index c477b8585a29..b6440657ef92 100644
--- a/arch/powerpc/kernel/stacktrace.c
+++ b/arch/powerpc/kernel/stacktrace.c
@@ -260,7 +260,7 @@ static void raise_backtrace_ipi(cpumask_t *mask)
 			pr_cont(" current pointer corrupt? (%px)\n", p->__current);
 
 		pr_warn("Back trace of paca->saved_r1 (0x%016llx) (possibly stale):\n", p->saved_r1);
-		show_stack(p->__current, (unsigned long *)p->saved_r1);
+		show_stack(p->__current, (unsigned long *)p->saved_r1, KERN_WARNING);
 	}
 }
 
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index 05bf537310a8..fde12a196706 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -105,18 +105,12 @@ static bool print_trace_address(unsigned long pc, void *arg)
 	return false;
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
 {
 	pr_cont("Call Trace:\n");
 	walk_stackframe(task, NULL, print_trace_address, (void *)loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
-
 static bool save_wchan(unsigned long pc, void *arg)
 {
 	if (!in_sched_functions(pc)) {
diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c
index 887a054919fc..0dc4b258b98d 100644
--- a/arch/s390/kernel/dumpstack.c
+++ b/arch/s390/kernel/dumpstack.c
@@ -126,7 +126,7 @@ int get_stack_info(unsigned long sp, struct task_struct *task,
 	return -EINVAL;
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+void show_stack(struct task_struct *task, unsigned long *stack,
 		       const char *loglvl)
 {
 	struct unwind_state state;
@@ -139,11 +139,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
 	debug_show_held_locks(task ? : current);
 }
 
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	show_stack_loglvl(task, stack, KERN_DEFAULT);
-}
-
 static void show_last_breaking_event(struct pt_regs *regs)
 {
 	printk("Last Breaking-Event-Address:\n");
@@ -181,7 +176,7 @@ void show_regs(struct pt_regs *regs)
 	show_registers(regs);
 	/* Show stack backtrace if pt_regs is from kernel mode */
 	if (!user_mode(regs))
-		show_stack(NULL, (unsigned long *) regs->gprs[15]);
+		show_stack(NULL, (unsigned long *) regs->gprs[15], KERN_DEFAULT);
 	show_last_breaking_event(regs);
 }
 
diff --git a/arch/sh/kernel/dumpstack.c b/arch/sh/kernel/dumpstack.c
index cc51e9d74667..a13c045804ed 100644
--- a/arch/sh/kernel/dumpstack.c
+++ b/arch/sh/kernel/dumpstack.c
@@ -144,8 +144,7 @@ void show_trace(struct task_struct *tsk, unsigned long *sp,
 	debug_show_held_locks(tsk);
 }
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
 {
 	unsigned long stack;
 
@@ -161,8 +160,3 @@ void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
 		 (unsigned long)task_stack_page(tsk));
 	show_trace(tsk, sp, NULL, loglvl);
 }
-
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
diff --git a/arch/sh/kernel/process_64.c b/arch/sh/kernel/process_64.c
index c2844a2e18cd..4c2144225c8e 100644
--- a/arch/sh/kernel/process_64.c
+++ b/arch/sh/kernel/process_64.c
@@ -275,13 +275,12 @@ void show_regs(struct pt_regs *regs)
 	 * If we're in kernel mode, dump the stack too..
 	 */
 	if (!user_mode(regs)) {
-		void show_stack(struct task_struct *tsk, unsigned long *sp);
 		unsigned long sp = regs->regs[15] & 0xffffffff;
 		struct task_struct *tsk = get_current();
 
 		tsk->thread.kregs = regs;
 
-		show_stack(tsk, (unsigned long *)sp);
+		show_stack(tsk, (unsigned long *)sp, KERN_DEFAULT);
 	}
 }
 
diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 0b07de5618e5..65c0d5207b0c 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -145,12 +145,10 @@ void show_regs(struct pt_regs *r)
 }
 
 /*
- * The show_stack(), show_stack_loglvl() are external APIs which
- * we do not use ourselves.
+ * The show_stack() is external API which we do not use ourselves.
  * The oops is printed in die_if_kernel.
  */
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
-		       const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl)
 {
 	unsigned long pc, fp;
 	unsigned long task_base;
@@ -179,11 +177,6 @@ void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
 	printk("%s\n", loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
-
 /*
  * Free current thread data structures etc..
  */
diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index 4282116e28e7..b2e3fe729b7e 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -195,7 +195,7 @@ void show_regs(struct pt_regs *regs)
 	       regs->u_regs[15]);
 	printk("RPC: <%pS>\n", (void *) regs->u_regs[15]);
 	show_regwindow(regs);
-	show_stack(current, (unsigned long *) regs->u_regs[UREG_FP]);
+	show_stack(current, (unsigned long *)regs->u_regs[UREG_FP], KERN_DEFAULT);
 }
 
 union global_cpu_snapshot global_cpu_snapshot[NR_CPUS];
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 8715bc93bd9d..96d92f107551 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -2453,8 +2453,7 @@ static void user_instruction_dump(unsigned int __user *pc)
 	printk("\n");
 }
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
-			 const char *loglvl)
+void show_stack(struct task_struct *tsk, unsigned long *_ksp, const char *loglvl)
 {
 	unsigned long fp, ksp;
 	struct thread_info *tp;
@@ -2514,11 +2513,6 @@ void show_stack_loglvl(struct task_struct *tsk, unsigned long *_ksp,
 	} while (++count < 16);
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *_ksp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
-
 static inline struct reg_window *kernel_stack_up(struct reg_window *rw)
 {
 	unsigned long fp = rw->ins[6];
diff --git a/arch/um/drivers/mconsole_kern.c b/arch/um/drivers/mconsole_kern.c
index 30575bd92975..a2e680f7d39f 100644
--- a/arch/um/drivers/mconsole_kern.c
+++ b/arch/um/drivers/mconsole_kern.c
@@ -648,7 +648,7 @@ static void stack_proc(void *arg)
 {
 	struct task_struct *task = arg;
 
-	show_stack(task, NULL);
+	show_stack(task, NULL, KERN_INFO);
 }
 
 /*
diff --git a/arch/um/kernel/sysrq.c b/arch/um/kernel/sysrq.c
index 1b54b6431499..acbc879d2773 100644
--- a/arch/um/kernel/sysrq.c
+++ b/arch/um/kernel/sysrq.c
@@ -27,7 +27,7 @@ static const struct stacktrace_ops stackops = {
 	.address = _print_addr
 };
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
+void show_stack(struct task_struct *task, unsigned long *stack,
 		       const char *loglvl)
 {
 	struct pt_regs *segv_regs = current->thread.segv_regs;
@@ -56,8 +56,3 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *stack,
 	dump_trace(current, &stackops, (void *)loglvl);
 	printk("%s\n", loglvl);
 }
-
-void show_stack(struct task_struct *task, unsigned long *stack)
-{
-	show_stack_loglvl(task, stack, KERN_INFO);
-}
diff --git a/arch/unicore32/kernel/traps.c b/arch/unicore32/kernel/traps.c
index 8b1335997f50..a3ac01df1a2e 100644
--- a/arch/unicore32/kernel/traps.c
+++ b/arch/unicore32/kernel/traps.c
@@ -167,18 +167,13 @@ static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 		c_backtrace(fp, loglvl);
 }
 
-void show_stack_loglvl(struct task_struct *tsk, unsigned long *sp,
+void show_stack(struct task_struct *tsk, unsigned long *sp,
 		       const char *loglvl)
 {
 	dump_backtrace(NULL, tsk, loglvl);
 	barrier();
 }
 
-void show_stack(struct task_struct *tsk, unsigned long *sp)
-{
-	show_stack_loglvl(tsk, sp, KERN_DEFAULT)
-}
-
 static int __die(const char *str, int err, struct thread_info *thread,
 		struct pt_regs *regs)
 {
diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 9d2c076be37a..5f816861f5d2 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -159,7 +159,7 @@ static void dump_leak(void)
 		return;
 	dump = 1;
 
-	show_stack_loglvl(NULL, NULL, KERN_ERR);
+	show_stack(NULL, NULL, KERN_ERR);
 	debug_dma_dump_mappings(NULL);
 }
 #endif
diff --git a/arch/x86/kernel/dumpstack.c b/arch/x86/kernel/dumpstack.c
index 4396f2cfad19..456511b2284e 100644
--- a/arch/x86/kernel/dumpstack.c
+++ b/arch/x86/kernel/dumpstack.c
@@ -279,7 +279,7 @@ void show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	}
 }
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
+void show_stack(struct task_struct *task, unsigned long *sp,
 		       const char *loglvl)
 {
 	task = task ? : current;
@@ -294,11 +294,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
 	show_trace_log_lvl(task, NULL, sp, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_DEFAULT);
-}
-
 void show_stack_regs(struct pt_regs *regs)
 {
 	show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
diff --git a/arch/xtensa/kernel/traps.c b/arch/xtensa/kernel/traps.c
index 3a50813eeb70..1671fbb816fa 100644
--- a/arch/xtensa/kernel/traps.c
+++ b/arch/xtensa/kernel/traps.c
@@ -501,8 +501,7 @@ static void show_trace(struct task_struct *task, unsigned long *sp,
 #define STACK_DUMP_LINE_SIZE 32
 static size_t kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
 
-void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
-		       const char *loglvl)
+void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
 {
 	size_t len;
 
@@ -519,11 +518,6 @@ void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
 	show_trace(task, stack, loglvl);
 }
 
-void show_stack(struct task_struct *task, unsigned long *sp)
-{
-	show_stack_loglvl(task, sp, KERN_INFO);
-}
-
 DEFINE_SPINLOCK(die_lock);
 
 void die(const char * str, struct pt_regs * regs, long err)
@@ -540,7 +534,7 @@ void die(const char * str, struct pt_regs * regs, long err)
 	pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter, pr);
 	show_regs(regs);
 	if (!user_mode(regs))
-		show_stack(NULL, (unsigned long*)regs->areg[1]);
+		show_stack(NULL, (unsigned long *)regs->areg[1], KERN_INFO);
 
 	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
 	spin_unlock_irq(&die_lock);
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index fc0108e65592..e38812a1c26a 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -519,7 +519,7 @@ static void dpm_watchdog_handler(struct timer_list *t)
 	struct dpm_watchdog *wd = from_timer(wd, t, timer);
 
 	dev_emerg(wd->dev, "**** DPM device timeout ****\n");
-	show_stack_loglvl(wd->tsk, NULL, KERN_EMERG);
+	show_stack(wd->tsk, NULL, KERN_EMERG);
 	panic("%s %s: unrecoverable failure\n",
 		dev_driver_string(wd->dev), dev_name(wd->dev));
 }
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index b11300b16f62..9a0910115c5c 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -232,7 +232,7 @@ static void showacpu(void *dummy)
 
 	raw_spin_lock_irqsave(&show_lock, flags);
 	pr_info("CPU%d:\n", smp_processor_id());
-	show_stack_loglvl(NULL, NULL, KERN_INFO);
+	show_stack(NULL, NULL, KERN_INFO);
 	raw_spin_unlock_irqrestore(&show_lock, flags);
 }
 
diff --git a/include/linux/sched/debug.h b/include/linux/sched/debug.h
index 373e4e3faf2a..00c45a0e6abe 100644
--- a/include/linux/sched/debug.h
+++ b/include/linux/sched/debug.h
@@ -30,9 +30,8 @@ extern void show_regs(struct pt_regs *);
  * task), SP is the stack pointer of the first frame that should be shown in the back
  * trace (or NULL if the entire call-chain of the task should be shown).
  */
-extern void show_stack(struct task_struct *task, unsigned long *sp);
-extern void show_stack_loglvl(struct task_struct *task, unsigned long *sp,
-			      const char *loglvl);
+extern void show_stack(struct task_struct *task, unsigned long *sp,
+		       const char *loglvl);
 
 extern void sched_show_task(struct task_struct *p);
 
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 43f5dcd2b9ac..18e03aba2cfc 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -30,7 +30,7 @@ static void kdb_show_stack(struct task_struct *p, void *addr)
 		kdb_dump_stack_on_cpu(kdb_process_cpu(p));
 		console_loglevel = old_lvl;
 	} else {
-		show_stack_loglvl(p, addr, KERN_EMERG);
+		show_stack(p, addr, KERN_EMERG);
 	}
 
 	kdb_trap_printk--;
diff --git a/kernel/locking/rtmutex-debug.c b/kernel/locking/rtmutex-debug.c
index 5e63d6e8a223..36e69100e8e0 100644
--- a/kernel/locking/rtmutex-debug.c
+++ b/kernel/locking/rtmutex-debug.c
@@ -125,7 +125,7 @@ void debug_rt_mutex_print_deadlock(struct rt_mutex_waiter *waiter)
 
 	printk("\n%s/%d's [blocked] stackdump:\n\n",
 		task->comm, task_pid_nr(task));
-	show_stack_loglvl(task, NULL, KERN_DEFAULT);
+	show_stack(task, NULL, KERN_DEFAULT);
 	printk("\n%s/%d's [current] stackdump:\n\n",
 		current->comm, task_pid_nr(current));
 	dump_stack();
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 581a219ac062..c8215a99a749 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5957,7 +5957,7 @@ void sched_show_task(struct task_struct *p)
 		(unsigned long)task_thread_info(p)->flags);
 
 	print_worker_info(KERN_INFO, p);
-	show_stack_loglvl(p, NULL, KERN_INFO);
+	show_stack(p, NULL, KERN_INFO);
 	put_task_stack(p);
 }
 EXPORT_SYMBOL_GPL(sched_show_task);
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 5595e8962cf6..a00ee6eedc7c 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -74,7 +74,7 @@ void show_regs_print_info(const char *log_lvl)
 static void __dump_stack(void)
 {
 	dump_stack_print_info(KERN_DEFAULT);
-	show_stack_loglvl(NULL, NULL, KERN_DEFAULT);
+	show_stack(NULL, NULL, KERN_DEFAULT);
 }
 
 /**
-- 
2.26.0

Re: [PATCHv3 00/50] Add log level to show_stack()

[Tetsuo Handa]

On 2020/04/19 5:18, Dmitry Safonov wrote:
> Add log level argument to show_stack().
> Done in three stages:
> 1. Introducing show_stack_loglvl() for every architecture
> 2. Migrating old users with an explicit log level
> 3. Renaming show_stack_loglvl() into show_stack()

Thank you for proposing this patchset.

Every architecture gets show_stack_loglvl() means that it will become
possible to implement dump_stack_loglvl(const char *loglvl), isn't it?

I'm about to start a proposal for making it possible to suppress printing majority of
OOM-killer messages and memory allocation failure messages to consoles
( https://lkml.kernel.org/r/efc649fc-f838-97ea-44a2-882f068d033c@i-love.sakura.ne.jp ), for
dump_stack() / show_mem() / dump_tasks() etc. can take long time (if printed to consoles) is
an unhappy thing for OOM context and atomic context.

Re: [PATCHv3 00/50] Add log level to show_stack()

[Dmitry Safonov]

Hi Tetsuo,

On 4/23/20 4:48 PM, Tetsuo Handa wrote:
> On 2020/04/19 5:18, Dmitry Safonov wrote:
>> Add log level argument to show_stack().
>> Done in three stages:
>> 1. Introducing show_stack_loglvl() for every architecture
>> 2. Migrating old users with an explicit log level
>> 3. Renaming show_stack_loglvl() into show_stack()
> 
> Thank you for proposing this patchset.
> 
> Every architecture gets show_stack_loglvl() means that it will become
> possible to implement dump_stack_loglvl(const char *loglvl), isn't it?

Yes, it should be quite trivial.

Currently I'm waiting if there will be any noise from linux-next, then I
plan to add dump_stack_loglvl(), also sched_show_task_lvl() and
show_trace().

> I'm about to start a proposal for making it possible to suppress printing majority of
> OOM-killer messages and memory allocation failure messages to consoles
> ( https://lkml.kernel.org/r/efc649fc-f838-97ea-44a2-882f068d033c@i-love.sakura.ne.jp ), for
> dump_stack() / show_mem() / dump_tasks() etc. can take long time (if printed to consoles) is
> an unhappy thing for OOM context and atomic context.

Sounds good - especially for slow consoles.
One can use sysrq to print OOM info.

Thanks,
          Dmitry