Re: [tip:perf/urgent] perf: Fix perf mmap bugs

From: Peter Zijlstra
Date: Wed Jun 05 2013 - 07:55:56 EST

On Tue, Jun 04, 2013 at 10:44:21AM +0200, Peter Zijlstra wrote:
> Ingo asked for a delta against the patch already included in -tip.
> Vince; perf_fuzzer crashed after about 5670000 iterations -- not sure
> you're aware it will crash at times. Anyway at this time accounting was
> still good.
> ---
> Subject: perf: Fix mmap() accounting hole
> Vince's fuzzer once again found holes. This time it spotted a leak in
> the locked page accounting.
> When an event had redirected output and its close() was the last
> reference to the buffer we didn't have a vm context to undo accounting.
> Change the code to destroy the buffer on the last munmap() and detach
> all redirected events at that time. This provides us the right context
> to undo the vm accounting.
> Reported-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
> Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Vince, can you confirm?
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