Messages in this thread Patch in this message | | | Date | Thu, 23 Apr 2009 14:23:27 +0200 | From | Andi Kleen <> | Subject | Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build |
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On Thu, Apr 23, 2009 at 02:02:19PM +0200, Johannes Weiner wrote: > > +{ > > + warn_slowpath_fmt(file, line, ""); > > +} > > +EXPORT_SYMBOL(warn_slowpath_null); > > That should still emit a warning due to passing in a zero-length > format string. Using (const char *){ 0 } as the literal would > suppress it (on gcc 4.3.3 at least) but I'm not sure if it's worth the > uglyness...
Hmm, you're right 3.3 generates a warning for that, 3.2 doesn't But at least it's only a single one, not thousands. Your trick would make sense. Updated patch attached.
-Andi
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Eliminate thousands of warnings with gcc 3.2 build v2
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.
v2: Avoid warning in warn_slowpath_null on newer gccs too (J.Weiner)
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> 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 2009-04-23 14:17:34.000000000 +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) { 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, (const char *) { 0 }); +} +EXPORT_SYMBOL(warn_slowpath_null); #endif #ifdef CONFIG_CC_STACKPROTECTOR
-- ak@linux.intel.com -- Speaking for myself only.
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