Re: [PATCH 1/3 v2] perf_event: fix race in perf_swevent_get_recursion_context()

From: Xiao Guangrong
Date: Tue Jan 19 2010 - 04:09:12 EST

Peter Zijlstra wrote:
> On Tue, 2010-01-19 at 16:37 +0800, Xiao Guangrong wrote:
>> It only disable preemption in perf_swevent_get_recursion_context(),
>> it can't avoid race of hard-irq and NMI since they are nested that
>> will re-enter this path and make the recursion value chaotic
>> In this patch, we use atomic operation to avoid it and reduce
>> cpu_ctx->recursion size, it also make this patch no need disable
>> preemption

Sorry, i forget the nesting of hard-irq is sequential, and not pollute
recursion value, thanks for you point out.

Hi Ingo,

Please ignore this patch, it not pollute other 2 patches in this

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