+ m68k-add-show_stack_loglvl.patch added to -mm tree

+ m68k-add-show_stack_loglvl.patch added to -mm tree

[akpm]

The patch titled
     Subject: m68k: add show_stack_loglvl()
has been added to the -mm tree.  Its filename is
     m68k-add-show_stack_loglvl.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/m68k-add-show_stack_loglvl.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/m68k-add-show_stack_loglvl.patch

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------------------------------------------------------
From: Dmitry Safonov <dima@arista.com>
Subject: m68k: 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/20200418201944.482088-18-dima@arista.com
Signed-off-by: Dmitry Safonov <dima@arista.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/m68k/kernel/traps.c |   16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

--- a/arch/m68k/kernel/traps.c~m68k-add-show_stack_loglvl
+++ a/arch/m68k/kernel/traps.c
@@ -811,13 +811,13 @@ asmlinkage void buserr_c(struct frame *f
 
 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
 	}
 	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
 		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);
 }
 
 /*
_

Patches currently in -mm which might be from dima@arista.com are

kallsyms-printk-add-loglvl-to-print_ip_sym.patch
alpha-add-show_stack_loglvl.patch
arc-add-show_stack_loglvl.patch
arm-asm-add-loglvl-to-c_backtrace.patch
arm-add-loglvl-to-unwind_backtrace.patch
arm-add-loglvl-to-dump_backtrace.patch
arm-wire-up-dump_backtrace_entrystm.patch
arm-add-show_stack_loglvl.patch
arm64-add-loglvl-to-dump_backtrace.patch
arm64-add-show_stack_loglvl.patch
c6x-add-show_stack_loglvl.patch
csky-add-show_stack_loglvl.patch
h8300-add-show_stack_loglvl.patch
hexagon-add-show_stack_loglvl.patch
ia64-pass-log-level-as-arg-into-ia64_do_show_stack.patch
ia64-add-show_stack_loglvl.patch
m68k-add-show_stack_loglvl.patch
microblaze-add-loglvl-to-microblaze_unwind_inner.patch
microblaze-add-loglvl-to-microblaze_unwind.patch
microblaze-add-show_stack_loglvl.patch
mips-add-show_stack_loglvl.patch
nds32-add-show_stack_loglvl.patch
nios2-add-show_stack_loglvl.patch
openrisc-add-show_stack_loglvl.patch
parisc-add-show_stack_loglvl.patch
powerpc-add-show_stack_loglvl.patch
riscv-add-show_stack_loglvl.patch
s390-add-show_stack_loglvl.patch
sh-add-loglvl-to-dump_mem.patch
sh-remove-needless-printk.patch
sh-add-loglvl-to-printk_address.patch
sh-add-loglvl-to-show_trace.patch
sh-add-show_stack_loglvl.patch
sparc-add-show_stack_loglvl.patch
um-sysrq-remove-needless-variable-sp.patch
um-add-show_stack_loglvl.patch
unicore32-remove-unused-pmode-argument-in-c_backtrace.patch
unicore32-add-loglvl-to-c_backtrace.patch
unicore32-add-show_stack_loglvl.patch
x86-add-missing-const-qualifiers-for-log_lvl.patch
x86-add-show_stack_loglvl.patch
xtensa-add-loglvl-to-show_trace.patch
xtensa-add-show_stack_loglvl.patch
sysrq-use-show_stack_loglvl.patch
x86-amd_gart-print-stacktrace-for-a-leak-with-kern_err.patch
power-use-show_stack_loglvl.patch
kdb-dont-play-with-console_loglevel.patch
sched-print-stack-trace-with-kern_info.patch
kernel-use-show_stack_loglvl.patch
kernel-rename-show_stack_loglvl-=-show_stack.patch