From 4469c0f17ec63dcc8c9ed512f4330b566c2c0d34 Mon Sep 17 00:00:00 2001
From: Alexander Potapenko <glider@google.com>
Date: Mon, 28 Jun 2021 19:40:30 -0700
Subject: [PATCH] printk: introduce dump_stack_lvl()
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.
[elver@google.com: add missing dump_stack_lvl() stub if CONFIG_PRINTK=n]
Link: https://lkml.kernel.org/r/YJ0KAM0hQev1AmWe@elver.google.com
Link: https://lkml.kernel.org/r/20210506105405.3535023-1-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
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: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
include/linux/printk.h | 5 +++++
lib/dump_stack.c | 20 +++++++++++++-------
2 files changed, 18 insertions(+), 7 deletions(-)
diff --git a/include/linux/printk.h b/include/linux/printk.h
index fe7eb2351610d..f589b8b608060 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);
@@ -269,6 +270,10 @@ static inline void show_regs_print_info(const char *log_lvl)
{
}
+static inline void dump_stack_lvl(const char *log_lvl)
+{
+}
+
static inline void dump_stack(void)
{
}
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index f5a33b6f773f7..586e3f2c6a158 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 @@ retry:
goto retry;
}
- __dump_stack();
+ __dump_stack(log_lvl);
if (!was_locked)
atomic_set(&dump_lock, -1);
@@ -125,9 +125,15 @@ retry:
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
+EXPORT_SYMBOL(dump_stack_lvl);
+
+asmlinkage __visible void dump_stack(void)
+{
+ dump_stack_lvl(KERN_DEFAULT);
+}
EXPORT_SYMBOL(dump_stack);
--
2.30.2