* [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
@ 2009-04-22 22:11 Andi Kleen
2009-04-23 11:58 ` Jesper Nilsson
2009-04-23 12:02 ` Johannes Weiner
0 siblings, 2 replies; 9+ messages in thread
From: Andi Kleen @ 2009-04-22 22:11 UTC (permalink / raw)
To: arjan, linux-kernel, torvalds, akpm
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)
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) {
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
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-22 22:11 [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build Andi Kleen
@ 2009-04-23 11:58 ` Jesper Nilsson
2009-04-23 12:18 ` Andi Kleen
2009-04-23 12:02 ` Johannes Weiner
1 sibling, 1 reply; 9+ messages in thread
From: Jesper Nilsson @ 2009-04-23 11:58 UTC (permalink / raw)
To: Andi Kleen; +Cc: arjan, linux-kernel, torvalds, akpm
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
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-22 22:11 [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build Andi Kleen
2009-04-23 11:58 ` Jesper Nilsson
@ 2009-04-23 12:02 ` Johannes Weiner
2009-04-23 12:23 ` Andi Kleen
1 sibling, 1 reply; 9+ messages in thread
From: Johannes Weiner @ 2009-04-23 12:02 UTC (permalink / raw)
To: Andi Kleen; +Cc: arjan, linux-kernel, torvalds, akpm
Hi Andi,
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)
>
> 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) {
> 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);
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...
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-23 11:58 ` Jesper Nilsson
@ 2009-04-23 12:18 ` Andi Kleen
0 siblings, 0 replies; 9+ messages in thread
From: Andi Kleen @ 2009-04-23 12:18 UTC (permalink / raw)
To: Jesper Nilsson; +Cc: Andi Kleen, arjan, linux-kernel, torvalds, akpm
On Thu, Apr 23, 2009 at 01:58:46PM +0200, Jesper Nilsson wrote:
> >
> > #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...
Noone in tree does according to grep. I would also argue
anyone doing that to be really broken.
>
> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Thanks.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-23 12:02 ` Johannes Weiner
@ 2009-04-23 12:23 ` Andi Kleen
2009-04-23 14:38 ` Johannes Weiner
0 siblings, 1 reply; 9+ messages in thread
From: Andi Kleen @ 2009-04-23 12:23 UTC (permalink / raw)
To: Johannes Weiner; +Cc: Andi Kleen, arjan, linux-kernel, torvalds, akpm
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
---
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.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-23 12:23 ` Andi Kleen
@ 2009-04-23 14:38 ` Johannes Weiner
2009-04-23 15:10 ` Andi Kleen
0 siblings, 1 reply; 9+ messages in thread
From: Johannes Weiner @ 2009-04-23 14:38 UTC (permalink / raw)
To: Andi Kleen; +Cc: arjan, linux-kernel, torvalds, akpm
On Thu, Apr 23, 2009 at 02:23:27PM +0200, Andi Kleen wrote:
> 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
>
> ---
>
> 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.
You are right:
text data bss dec hex filename
4802274 707668 712704 6222646 5ef336 vmlinux
text data bss dec hex filename
4799027 703572 712704 6215303 5ed687 vmlinux
> 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);
I would WTF here without knowing the warning. Can you add a comment?
Otherwise, Acked-by: Johannes Weiner <hannes@cmpxchg.org>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-23 15:10 ` Andi Kleen
@ 2009-04-23 15:07 ` Arjan van de Ven
2009-04-23 15:23 ` Andi Kleen
0 siblings, 1 reply; 9+ messages in thread
From: Arjan van de Ven @ 2009-04-23 15:07 UTC (permalink / raw)
To: Andi Kleen; +Cc: Johannes Weiner, linux-kernel, torvalds, akpm
Andi Kleen wrote:
> On Thu, Apr 23, 2009 at 04:38:59PM +0200, Johannes Weiner wrote:
>>> +void warn_slowpath_null(const char *file, int line)
>>> +{
>>> + warn_slowpath_fmt(file, line, (const char *) { 0 });
>>> +}
>>> +EXPORT_SYMBOL(warn_slowpath_null);
>> I would WTF here without knowing the warning. Can you add a comment?
>>
>> Otherwise, Acked-by: Johannes Weiner <hannes@cmpxchg.org>
>
> Ok version with comment.
Makes sense if we plan to keep gcc 3.2 supported; if we plan to drop it then we shouldn't bother.
Anyway
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-23 14:38 ` Johannes Weiner
@ 2009-04-23 15:10 ` Andi Kleen
2009-04-23 15:07 ` Arjan van de Ven
0 siblings, 1 reply; 9+ messages in thread
From: Andi Kleen @ 2009-04-23 15:10 UTC (permalink / raw)
To: Johannes Weiner; +Cc: Andi Kleen, arjan, linux-kernel, torvalds, akpm
On Thu, Apr 23, 2009 at 04:38:59PM +0200, Johannes Weiner wrote:
> > +void warn_slowpath_null(const char *file, int line)
> > +{
> > + warn_slowpath_fmt(file, line, (const char *) { 0 });
> > +}
> > +EXPORT_SYMBOL(warn_slowpath_null);
>
> I would WTF here without knowing the warning. Can you add a comment?
>
> Otherwise, Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Ok version with comment.
-Andi
---
Eliminate thousands of warnings with gcc 3.2 build v3
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 also shrinks the kernel slightly:
text data bss dec hex filename
4802274 707668 712704 6222646 5ef336 vmlinux
text data bss dec hex filename
4799027 703572 712704 6215303 5ed687 vmlinux
v2: Avoid warning in warn_slowpath_null on newer gccs too (J.Weiner)
v3: add comment, size numbers
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
include/asm-generic/bug.h | 7 ++++---
kernel/panic.c | 13 ++++++++++---
2 files changed, 14 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 17:05:01.000000000 +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 +369,14 @@
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)
+{
+ /* The { 0 } avoids a gcc format warning */
+ 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.
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build
2009-04-23 15:07 ` Arjan van de Ven
@ 2009-04-23 15:23 ` Andi Kleen
0 siblings, 0 replies; 9+ messages in thread
From: Andi Kleen @ 2009-04-23 15:23 UTC (permalink / raw)
To: Arjan van de Ven
Cc: Andi Kleen, Johannes Weiner, linux-kernel, torvalds, akpm
On Thu, Apr 23, 2009 at 08:07:51AM -0700, Arjan van de Ven wrote:
> Andi Kleen wrote:
> >On Thu, Apr 23, 2009 at 04:38:59PM +0200, Johannes Weiner wrote:
> >>>+void warn_slowpath_null(const char *file, int line)
> >>>+{
> >>>+ warn_slowpath_fmt(file, line, (const char *) { 0 });
> >>>+}
> >>>+EXPORT_SYMBOL(warn_slowpath_null);
> >>I would WTF here without knowing the warning. Can you add a comment?
> >>
> >>Otherwise, Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> >
> >Ok version with comment.
>
> Makes sense if we plan to keep gcc 3.2 supported; if we plan to drop it
> then we shouldn't bother.
It helps even for other compilers for code size, at least it shrunk Johannes'
kernel by about 3k
> Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Thanks.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2009-04-23 15:19 UTC | newest]
Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-04-22 22:11 [PATCH] Eliminate thousands of warnings in WARN_ON with gcc 3.2 build Andi Kleen
2009-04-23 11:58 ` Jesper Nilsson
2009-04-23 12:18 ` Andi Kleen
2009-04-23 12:02 ` Johannes Weiner
2009-04-23 12:23 ` Andi Kleen
2009-04-23 14:38 ` Johannes Weiner
2009-04-23 15:10 ` Andi Kleen
2009-04-23 15:07 ` Arjan van de Ven
2009-04-23 15:23 ` Andi Kleen
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