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SubjectRe: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
On Thu, Apr 23, 2009 at 12:11:34AM +0200, Andi Kleen wrote:
> Eliminate thousands of warnings with gcc 3.2 build
>
> When building with gcc 3.2 I get thousands of warnings about passing
> a NULL format string to warn_on_slowpath(). Split this case out
> into a separate call. This should also shrink the kernel
> slightly in theory (haven't done numbers)

I've run into this also, it would be good to get rid of all those warnings.

> Signed-off-by: Andi Kleen <ak@linux.intel.com>
>
> ---
> include/asm-generic/bug.h | 7 ++++---
> kernel/panic.c | 12 +++++++++---
> 2 files changed, 13 insertions(+), 6 deletions(-)
>
> Index: linux-2.6.30-rc2-ak/include/asm-generic/bug.h
> ===================================================================
> --- linux-2.6.30-rc2-ak.orig/include/asm-generic/bug.h 2009-01-11 20:20:40.000000000 +0100
> +++ linux-2.6.30-rc2-ak/include/asm-generic/bug.h 2009-04-22 23:52:48.000000000 +0200
> @@ -58,12 +58,13 @@
> */
> #ifndef __WARN
> #ifndef __ASSEMBLY__
> -extern void warn_slowpath(const char *file, const int line,
> +extern void warn_slowpath_fmt(const char *file, const int line,
> const char *fmt, ...) __attribute__((format(printf, 3, 4)));
> +extern void warn_slowpath_null(const char *file, const int line);
> #define WANT_WARN_ON_SLOWPATH
> #endif
> -#define __WARN() warn_slowpath(__FILE__, __LINE__, NULL)
> -#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
> +#define __WARN() warn_slowpath_null(__FILE__, __LINE__)
> +#define __WARN_printf(arg...) warn_slowpath_fmt(__FILE__, __LINE__, arg)
> #else
> #define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
> #endif
> Index: linux-2.6.30-rc2-ak/kernel/panic.c
> ===================================================================
> --- linux-2.6.30-rc2-ak.orig/kernel/panic.c 2009-04-19 19:29:07.000000000 +0200
> +++ linux-2.6.30-rc2-ak/kernel/panic.c 2009-04-22 23:53:55.000000000 +0200
> @@ -342,7 +342,7 @@
> }
>
> #ifdef WANT_WARN_ON_SLOWPATH
> -void warn_slowpath(const char *file, int line, const char *fmt, ...)
> +void warn_slowpath_fmt(const char *file, int line, const char *fmt, ...)
> {
> va_list args;
> char function[KSYM_SYMBOL_LEN];
> @@ -358,7 +358,7 @@
> if (board)
> printk(KERN_WARNING "Hardware name: %s\n", board);
>
> - if (fmt) {
> + if (*fmt) {

Is this completely safe? If somebody is stupid enough to call
WARN(condition, NULL); this won't work as it did before.
OTOH, it would still be useless in debugging...

> va_start(args, fmt);
> vprintk(fmt, args);
> va_end(args);
> @@ -369,7 +369,13 @@
> print_oops_end_marker();
> add_taint(TAINT_WARN);
> }
> -EXPORT_SYMBOL(warn_slowpath);
> +EXPORT_SYMBOL(warn_slowpath_fmt);
> +
> +void warn_slowpath_null(const char *file, int line)
> +{
> + warn_slowpath_fmt(file, line, "");
> +}
> +EXPORT_SYMBOL(warn_slowpath_null);
> #endif
>
> #ifdef CONFIG_CC_STACKPROTECTOR

Otherwise:

Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>

/^JN - Jesper Nilsson
--
Jesper Nilsson -- jesper.nilsson@axis.com


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