Re: [PATCH 2/2] warn: print the DMI board info name in aWARN/WARN_ON

From: Ingo Molnar
Date: Fri Nov 28 2008 - 12:00:52 EST



* Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> wrote:

> From acdc8771dfaf6e8236b9122364301f65f46d4b59 Mon Sep 17 00:00:00 2001
> From: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
> 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 <arjan@xxxxxxxxxxxxxxx>
> ---
> 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
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