lkml.org 
[lkml]   [2007]   [Aug]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Kgdb-bugreport] 2.6.23-rc3-mm1: kgdb build failure on powerpc
Andrew Morton wrote:
> On Wed, 22 Aug 2007 17:44:12 -0500
> Jason Wessel <jason.wessel@windriver.com> wrote:
>
>
>> + while (!atomic_read(&debugger_active));
>>
>
> eek. We're in the process of hunting down and eliminating exactly this
> construct. There have been cases where the compiler cached the
> atomic_read() result in a register, turning the above into an infinite
> loop.
>
> Plus we should never add power-burners like that into the kernel anyway.
> That loop should have a cpu_relax() in it. Which will also fix the
> compiler problem described above.
>
>
Agreed, and fixed with a cpu_relax.

> Thirdly, please always add a newline when coding statements like that:
>
> while (expr())
> ;
>

The other instances I found of the same problem in the kgdb core are
fixed too.

I merged all the changes into the for_mm branch in the kgdb git tree.

Thanks,
Jason.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-08-23 05:27    [from the cache]
©2003-2011 Jasper Spaans