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SubjectRe: [PATCH] let WARN_ON() output the condition
On Wed, 6 Dec 2006 01:51:01 +0100 (CET)
Jiri Kosina <jkosina@suse.cz> wrote:

> [PATCH] let WARN_ON() output the condition
>
> It is possible, in some cases, that the output of WARN_ON() is ambiguous
> and can't be properly used to identify the exact condition which caused
> the warning to trigger. This happens whenever there is a macro that
> contains multiple WARN_ONs inside. Notable example is spin_lock_mutex().
> If any of the two WARN_ONs trigger, we are not able to say which one was
> the cause (as we get only line number, which however belongs to the place
> where the macro was expanded).
>
> This patch lets WARN_ON() to output also the condition and fixes the
> DEBUG_LOCKS_WARN_ON() macro to pass the condition properly to WARN_ON. The
> possible drawback could be when someone passes a condition which has
> sideeffects. Then it would be evaluated twice, instead of current one
> evaluation. On the other hand, when anyone passes expression with
> sideeffects to WARN_ON(), he is asking for problems anyway.
>
> Patch against 2.6.19-rc6-mm2.
>
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>
> ---
>
> include/asm-generic/bug.h | 4 ++--
> include/linux/debug_locks.h | 2 +-
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
> index a06eecd..af7574e 100644
> --- a/include/asm-generic/bug.h
> +++ b/include/asm-generic/bug.h
> @@ -35,8 +35,8 @@ #ifndef HAVE_ARCH_WARN_ON
> #define WARN_ON(condition) ({ \
> typeof(condition) __ret_warn_on = (condition); \
> if (unlikely(__ret_warn_on)) { \
> - printk("WARNING at %s:%d %s()\n", __FILE__, \
> - __LINE__, __FUNCTION__); \
> + printk("WARNING (%s) at %s:%d %s()\n", #condition, \
> + __FILE__,__LINE__, __FUNCTION__); \
> dump_stack(); \
> } \
> unlikely(__ret_warn_on); \
> diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
> index 952bee7..1c2b682 100644
> --- a/include/linux/debug_locks.h
> +++ b/include/linux/debug_locks.h
> @@ -25,7 +25,7 @@ ({ \
> \
> if (unlikely(c)) { \
> if (debug_locks_off()) \
> - WARN_ON(1); \
> + WARN_ON(c); \
> __ret = 1; \
> } \
> __ret; \

Give me an additional 5k of text with distro config. Is it worth it?

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