2008-11-28 16:35:22

by Arjan van de Ven

[permalink] [raw]
Subject: [PATCH 1/2] warn: consolidate warn_slowpath and warn_on_slowpath

>From 7aaa8478fe22e944adf185e465fa07799b87e573 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <[email protected]>
Date: Fri, 28 Nov 2008 08:30:46 -0800
Subject: [PATCH] warn: consolidate warn_slowpath and warn_on_slowpath

warn_slowpath is a superset of warn_on_slowpath; just have
warn_on_slowpath call warn_slowpath with a NULL 3rd argument.

Signed-off-by: Arjan van de Ven <[email protected]>
---
kernel/panic.c | 32 ++++++++++++--------------------
1 files changed, 12 insertions(+), 20 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index d1ac662..2b913aa 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -324,23 +324,6 @@ void oops_exit(void)
}

#ifdef WANT_WARN_ON_SLOWPATH
-void warn_on_slowpath(const char *file, int line)
-{
- char function[KSYM_SYMBOL_LEN];
- unsigned long caller = (unsigned long) __builtin_return_address(0);
- sprint_symbol(function, caller);
-
- printk(KERN_WARNING "------------[ cut here ]------------\n");
- printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
- line, function);
- print_modules();
- dump_stack();
- print_oops_end_marker();
- add_taint(TAINT_WARN);
-}
-EXPORT_SYMBOL(warn_on_slowpath);
-
-
void warn_slowpath(const char *file, int line, const char *fmt, ...)
{
va_list args;
@@ -351,9 +334,12 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
printk(KERN_WARNING "------------[ cut here ]------------\n");
printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
line, function);
- va_start(args, fmt);
- vprintk(fmt, args);
- va_end(args);
+
+ if (fmt) {
+ va_start(args, fmt);
+ vprintk(fmt, args);
+ va_end(args);
+ }

print_modules();
dump_stack();
@@ -361,6 +347,12 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
add_taint(TAINT_WARN);
}
EXPORT_SYMBOL(warn_slowpath);
+
+void warn_on_slowpath(const char *file, int line)
+{
+ warn_slowpath(file, line, NULL);
+}
+EXPORT_SYMBOL(warn_on_slowpath);
#endif

#ifdef CONFIG_CC_STACKPROTECTOR
--
1.6.0.4



--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org


2008-11-28 16:35:41

by Arjan van de Ven

[permalink] [raw]
Subject: [PATCH 2/2] warn: print the DMI board info name in a WARN/WARN_ON

>From acdc8771dfaf6e8236b9122364301f65f46d4b59 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <[email protected]>
Date: Fri, 28 Nov 2008 08:32:44 -0800
Subject: [PATCH] warn: print the DMI board info name in a WARN/WARN_ON

it's very useful for many low level WARN_ON's to find out which
motherboard has the broken BIOS etc... this patch adds a printk
to the WARN_ON code for this.
On architectures without DMI, gcc should optimize the code out.

Signed-off-by: Arjan van de Ven <[email protected]>
---
kernel/panic.c | 5 +++++
1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/kernel/panic.c b/kernel/panic.c
index 2b913aa..9c1b7e0 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -21,6 +21,7 @@
#include <linux/debug_locks.h>
#include <linux/random.h>
#include <linux/kallsyms.h>
+#include <linux/dmi.h>

int panic_on_oops;
static unsigned long tainted_mask;
@@ -328,12 +329,16 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
{
va_list args;
char function[KSYM_SYMBOL_LEN];
+ const char *board;
unsigned long caller = (unsigned long)__builtin_return_address(0);
sprint_symbol(function, caller);

printk(KERN_WARNING "------------[ cut here ]------------\n");
printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
line, function);
+ board = dmi_get_system_info(DMI_PRODUCT_NAME);
+ if (board)
+ printk(KERN_WARNING "Hardware name: %s\n", board);

if (fmt) {
va_start(args, fmt);
--
1.6.0.4




--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org

2008-11-28 16:58:08

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH 1/2] warn: consolidate warn_slowpath and warn_on_slowpath


* Arjan van de Ven <[email protected]> wrote:

> From 7aaa8478fe22e944adf185e465fa07799b87e573 Mon Sep 17 00:00:00 2001
> From: Arjan van de Ven <[email protected]>
> Date: Fri, 28 Nov 2008 08:30:46 -0800
> Subject: [PATCH] warn: consolidate warn_slowpath and warn_on_slowpath
>
> warn_slowpath is a superset of warn_on_slowpath; just have
> warn_on_slowpath call warn_slowpath with a NULL 3rd argument.
>
> Signed-off-by: Arjan van de Ven <[email protected]>
> ---
> kernel/panic.c | 32 ++++++++++++--------------------
> 1 files changed, 12 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/panic.c b/kernel/panic.c
> index d1ac662..2b913aa 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -324,23 +324,6 @@ void oops_exit(void)
> }
>
> #ifdef WANT_WARN_ON_SLOWPATH
> -void warn_on_slowpath(const char *file, int line)
> -{
> - char function[KSYM_SYMBOL_LEN];
> - unsigned long caller = (unsigned long) __builtin_return_address(0);
> - sprint_symbol(function, caller);
> -
> - printk(KERN_WARNING "------------[ cut here ]------------\n");
> - printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
> - line, function);
> - print_modules();
> - dump_stack();
> - print_oops_end_marker();
> - add_taint(TAINT_WARN);
> -}
> -EXPORT_SYMBOL(warn_on_slowpath);
> -
> -
> void warn_slowpath(const char *file, int line, const char *fmt, ...)
> {
> va_list args;
> @@ -351,9 +334,12 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
> printk(KERN_WARNING "------------[ cut here ]------------\n");
> printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
> line, function);
> - va_start(args, fmt);
> - vprintk(fmt, args);
> - va_end(args);
> +
> + if (fmt) {
> + va_start(args, fmt);
> + vprintk(fmt, args);
> + va_end(args);
> + }
>
> print_modules();
> dump_stack();
> @@ -361,6 +347,12 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
> add_taint(TAINT_WARN);
> }
> EXPORT_SYMBOL(warn_slowpath);
> +
> +void warn_on_slowpath(const char *file, int line)
> +{
> + warn_slowpath(file, line, NULL);
> +}
> +EXPORT_SYMBOL(warn_on_slowpath);
> #endif

well spotted! Applied to tip/core/debug, thanks Arjan!

I've also done the change below that goes one step further, and turns
eliminates warn_on_slowpath() altogether and calls warn_slowpath(file,
line, NULL) straight from include/asm-generic/bug.h's __WARN()
definition.

Ingo

------------->
>From ec5679e513305f1411753e5f5489935bd638af23 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <[email protected]>
Date: Fri, 28 Nov 2008 17:56:14 +0100
Subject: [PATCH] debug warnings: eliminate warn_on_slowpath()

Impact: cleanup, eliminate code

now that warn_on_slowpath() uses warn_slowpath(...,NULL), we can
eliminate warn_on_slowpath() altogether and use warn_slowpath().

Signed-off-by: Ingo Molnar <[email protected]>
---
include/asm-generic/bug.h | 7 +++----
kernel/panic.c | 6 ------
2 files changed, 3 insertions(+), 10 deletions(-)

diff --git a/include/asm-generic/bug.h b/include/asm-generic/bug.h
index 12c07c1..b8ba694 100644
--- a/include/asm-generic/bug.h
+++ b/include/asm-generic/bug.h
@@ -33,15 +33,14 @@ struct bug_entry {

#ifndef __WARN
#ifndef __ASSEMBLY__
-extern void warn_on_slowpath(const char *file, const int line);
extern void warn_slowpath(const char *file, const int line,
const char *fmt, ...) __attribute__((format(printf, 3, 4)));
#define WANT_WARN_ON_SLOWPATH
#endif
-#define __WARN() warn_on_slowpath(__FILE__, __LINE__)
-#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
+#define __WARN() warn_slowpath(__FILE__, __LINE__, NULL)
+#define __WARN_printf(arg...) warn_slowpath(__FILE__, __LINE__, arg)
#else
-#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
+#define __WARN_printf(arg...) do { printk(arg); __WARN(); } while (0)
#endif

#ifndef WARN_ON
diff --git a/kernel/panic.c b/kernel/panic.c
index 73d3651..50349a4 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -349,12 +349,6 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
add_taint(TAINT_WARN);
}
EXPORT_SYMBOL(warn_slowpath);
-
-void warn_on_slowpath(const char *file, int line)
-{
- warn_slowpath(file, line, NULL);
-}
-EXPORT_SYMBOL(warn_on_slowpath);
#endif

#ifdef CONFIG_CC_STACKPROTECTOR

2008-11-28 17:00:51

by Ingo Molnar

[permalink] [raw]
Subject: Re: [PATCH 2/2] warn: print the DMI board info name in a WARN/WARN_ON


* Arjan van de Ven <[email protected]> wrote:

> From acdc8771dfaf6e8236b9122364301f65f46d4b59 Mon Sep 17 00:00:00 2001
> From: Arjan van de Ven <[email protected]>
> Date: Fri, 28 Nov 2008 08:32:44 -0800
> Subject: [PATCH] warn: print the DMI board info name in a WARN/WARN_ON
>
> it's very useful for many low level WARN_ON's to find out which
> motherboard has the broken BIOS etc... this patch adds a printk
> to the WARN_ON code for this.
> On architectures without DMI, gcc should optimize the code out.
>
> Signed-off-by: Arjan van de Ven <[email protected]>
> ---
> kernel/panic.c | 5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
> diff --git a/kernel/panic.c b/kernel/panic.c
> index 2b913aa..9c1b7e0 100644
> --- a/kernel/panic.c
> +++ b/kernel/panic.c
> @@ -21,6 +21,7 @@
> #include <linux/debug_locks.h>
> #include <linux/random.h>
> #include <linux/kallsyms.h>
> +#include <linux/dmi.h>
>
> int panic_on_oops;
> static unsigned long tainted_mask;
> @@ -328,12 +329,16 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
> {
> va_list args;
> char function[KSYM_SYMBOL_LEN];
> + const char *board;
> unsigned long caller = (unsigned long)__builtin_return_address(0);
> sprint_symbol(function, caller);
>
> printk(KERN_WARNING "------------[ cut here ]------------\n");
> printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
> line, function);
> + board = dmi_get_system_info(DMI_PRODUCT_NAME);
> + if (board)
> + printk(KERN_WARNING "Hardware name: %s\n", board);
>
> if (fmt) {
> va_start(args, fmt);

nice idea - applied to tip/core/debug.

On architectures (or systems) where there's no DMI_PRODUCT_NAME string
available, we'll print nothing. It's also a simple lockless call so can
be called from any context.

Andrew, any objections?

Ingo

2008-11-28 19:53:11

by Andrew Morton

[permalink] [raw]
Subject: Re: [PATCH 2/2] warn: print the DMI board info name in a WARN/WARN_ON

On Fri, 28 Nov 2008 18:00:29 +0100 Ingo Molnar <[email protected]> wrote:

>
> * Arjan van de Ven <[email protected]> wrote:
>
> > From acdc8771dfaf6e8236b9122364301f65f46d4b59 Mon Sep 17 00:00:00 2001
> > From: Arjan van de Ven <[email protected]>
> > Date: Fri, 28 Nov 2008 08:32:44 -0800
> > Subject: [PATCH] warn: print the DMI board info name in a WARN/WARN_ON
> >
> > it's very useful for many low level WARN_ON's to find out which
> > motherboard has the broken BIOS etc... this patch adds a printk
> > to the WARN_ON code for this.
> > On architectures without DMI, gcc should optimize the code out.
> >
> > Signed-off-by: Arjan van de Ven <[email protected]>
> > ---
> > kernel/panic.c | 5 +++++
> > 1 files changed, 5 insertions(+), 0 deletions(-)
> >
> > diff --git a/kernel/panic.c b/kernel/panic.c
> > index 2b913aa..9c1b7e0 100644
> > --- a/kernel/panic.c
> > +++ b/kernel/panic.c
> > @@ -21,6 +21,7 @@
> > #include <linux/debug_locks.h>
> > #include <linux/random.h>
> > #include <linux/kallsyms.h>
> > +#include <linux/dmi.h>
> >
> > int panic_on_oops;
> > static unsigned long tainted_mask;
> > @@ -328,12 +329,16 @@ void warn_slowpath(const char *file, int line, const char *fmt, ...)
> > {
> > va_list args;
> > char function[KSYM_SYMBOL_LEN];
> > + const char *board;
> > unsigned long caller = (unsigned long)__builtin_return_address(0);
> > sprint_symbol(function, caller);
> >
> > printk(KERN_WARNING "------------[ cut here ]------------\n");
> > printk(KERN_WARNING "WARNING: at %s:%d %s()\n", file,
> > line, function);
> > + board = dmi_get_system_info(DMI_PRODUCT_NAME);
> > + if (board)
> > + printk(KERN_WARNING "Hardware name: %s\n", board);
> >
> > if (fmt) {
> > va_start(args, fmt);
>
> nice idea - applied to tip/core/debug.
>
> On architectures (or systems) where there's no DMI_PRODUCT_NAME string
> available, we'll print nothing. It's also a simple lockless call so can
> be called from any context.
>
> Andrew, any objections?
>

Nope. This is the first time we've included dmi.h from such a core
place, but afaict all architectures should have encountered that file
by now.