Re: [PATCH] perf,x86: fix kernel crash with PEBS/BTS after suspend/resume

[Shuah Khan]

On Fri, Mar 15, 2013 at 2:31 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Fri, Mar 15, 2013 at 02:26:07PM +0100, Stephane Eranian wrote:
>>
>> This patch fixes a kernel crash when using precise sampling (PEBS)
>> after a suspend/resume. Turns out the CPU notifier code is not invoked
>> on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly
>> by the kernel and keeps it power-on/resume value of 0 causing any PEBS
>> measurement to crash when running on CPU0.
>>
>> The workaround is to add a hook in the actual resume code to restore
>> the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0,
>> the DS_AREA will be restored twice but this is harmless.
>>
>> Reported-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
>> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
>> ---
>
> Is this needed for the 3.8 or older kernels as well?
>
> thanks,
>
> greg k-h

Just about to ask the same question. Patch applies to 3.8, 3.4, 3.2
and 3.5. But needs some massaging for 3.0. I have the kernels built,
haven't started testing yet.

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