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* [PATCH 1/2] printk: introduce dump_stack_lvl()
@ 2021-05-05  9:22 Alexander Potapenko
  2021-05-05  9:22 ` [PATCH 2/2] kasan: use dump_stack_lvl(KERN_ERR) to print stacks Alexander Potapenko
  2021-05-05 10:37 ` [PATCH 1/2] printk: introduce dump_stack_lvl() Marco Elver
  0 siblings, 2 replies; 4+ messages in thread
From: Alexander Potapenko @ 2021-05-05  9:22 UTC (permalink / raw)
  To: akpm, pmladek, mingo
  Cc: bo.he, yanmin_zhang, psodagud, dvyukov, elver, linux-kernel,
	ryabinin.a.a, Alexander Potapenko, he

dump_stack() is used for many different cases, which may require a log
level consistent with other kernel messages surrounding the dump_stack()
call.
Without that, certain systems that are configured to ignore the default
level messages will miss stack traces in critical error reports.

This patch introduces dump_stack_lvl() that behaves similarly to
dump_stack(), but accepts a custom log level.
The old dump_stack() becomes equal to dump_stack_lvl(KERN_DEFAULT).

A somewhat similar patch has been proposed in 2012:
https://lore.kernel.org/lkml/1332493269.2359.9.camel@hebo/
, but wasn't merged.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: he, bo <bo.he@intel.com>
Cc: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Cc: Prasad Sodagudi <psodagud@quicinc.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alexander Potapenko <glider@google.com>
---
 include/linux/printk.h |  1 +
 lib/dump_stack.c       | 19 ++++++++++++-------
 2 files changed, 13 insertions(+), 7 deletions(-)

diff --git a/include/linux/printk.h b/include/linux/printk.h
index fe7eb2351610..abe274305d79 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -206,6 +206,7 @@ void __init setup_log_buf(int early);
 __printf(1, 2) void dump_stack_set_arch_desc(const char *fmt, ...);
 void dump_stack_print_info(const char *log_lvl);
 void show_regs_print_info(const char *log_lvl);
+extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold;
 extern asmlinkage void dump_stack(void) __cold;
 extern void printk_safe_flush(void);
 extern void printk_safe_flush_on_panic(void);
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index f5a33b6f773f..3d2c324a4929 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -73,10 +73,10 @@ void show_regs_print_info(const char *log_lvl)
 	dump_stack_print_info(log_lvl);
 }
 
-static void __dump_stack(void)
+static void __dump_stack(const char *log_lvl)
 {
-	dump_stack_print_info(KERN_DEFAULT);
-	show_stack(NULL, NULL, KERN_DEFAULT);
+	dump_stack_print_info(log_lvl);
+	show_stack(NULL, NULL, log_lvl);
 }
 
 /**
@@ -87,7 +87,7 @@ static void __dump_stack(void)
 #ifdef CONFIG_SMP
 static atomic_t dump_lock = ATOMIC_INIT(-1);
 
-asmlinkage __visible void dump_stack(void)
+asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
 {
 	unsigned long flags;
 	int was_locked;
@@ -117,7 +117,7 @@ asmlinkage __visible void dump_stack(void)
 		goto retry;
 	}
 
-	__dump_stack();
+	__dump_stack(log_lvl);
 
 	if (!was_locked)
 		atomic_set(&dump_lock, -1);
@@ -125,9 +125,14 @@ asmlinkage __visible void dump_stack(void)
 	local_irq_restore(flags);
 }
 #else
-asmlinkage __visible void dump_stack(void)
+asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
 {
-	__dump_stack();
+	__dump_stack(log_lvl);
 }
 #endif
+
+asmlinkage __visible void dump_stack(void)
+{
+	dump_stack_lvl(KERN_DEFAULT);
+}
 EXPORT_SYMBOL(dump_stack);
-- 
2.31.1.527.g47e6f16901-goog


^ permalink raw reply related	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-05-05 10:58 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-05-05  9:22 [PATCH 1/2] printk: introduce dump_stack_lvl() Alexander Potapenko
2021-05-05  9:22 ` [PATCH 2/2] kasan: use dump_stack_lvl(KERN_ERR) to print stacks Alexander Potapenko
2021-05-05 10:37 ` [PATCH 1/2] printk: introduce dump_stack_lvl() Marco Elver
2021-05-05 10:58   ` Alexander Potapenko

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