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

From: Greg KH
Date: Fri Mar 15 2013 - 16:31:31 EST


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
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