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| author | Andi Kleen <ak@linux.intel.com> | 2017-11-18 00:27:03 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-18 01:10:00 +0100 |
| commit | b1fca27d384e8418aac84b39f6f5179aecc1b64f (patch) | |
| tree | e08be97de59a1cbb16df46273aadef161358b8ba /kernel/panic.c | |
| parent | sh/boot: add static stack-protector to pre-kernel (diff) | |
| download | linux-b1fca27d384e8418aac84b39f6f5179aecc1b64f.tar.xz linux-b1fca27d384e8418aac84b39f6f5179aecc1b64f.zip | |
kernel debug: support resetting WARN*_ONCE
I like _ONCE warnings because it's guaranteed that they don't flood the
log.
During testing I find it useful to reset the state of the once warnings,
so that I can rerun tests and see if they trigger again, or can
guarantee that a test run always hits the same warnings.
This patch adds a debugfs interface to reset all the _ONCE warnings so
that they appear again:
echo 1 > /sys/kernel/debug/clear_warn_once
This is implemented by putting all the warning booleans into a special
section, and clearing it.
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20171017221455.6740-1-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/panic.c')
| -rw-r--r-- | kernel/panic.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/kernel/panic.c b/kernel/panic.c index bdd18afa19a4..672a91dc20fe 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -27,6 +27,8 @@ #include <linux/console.h> #include <linux/bug.h> #include <linux/ratelimit.h> +#include <linux/debugfs.h> +#include <asm/sections.h> #define PANIC_TIMER_STEP 100 #define PANIC_BLINK_SPD 18 @@ -587,6 +589,32 @@ void warn_slowpath_null(const char *file, int line) EXPORT_SYMBOL(warn_slowpath_null); #endif +#ifdef CONFIG_BUG + +/* Support resetting WARN*_ONCE state */ + +static int clear_warn_once_set(void *data, u64 val) +{ + memset(__start_once, 0, __end_once - __start_once); + return 0; +} + +DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops, + NULL, + clear_warn_once_set, + "%lld\n"); + +static __init int register_warn_debugfs(void) +{ + /* Don't care about failure */ + debugfs_create_file("clear_warn_once", 0644, NULL, + NULL, &clear_warn_once_fops); + return 0; +} + +device_initcall(register_warn_debugfs); +#endif + #ifdef CONFIG_CC_STACKPROTECTOR /* |