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From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Paul Mackerras <paulus@samba.org>,
	Masami Hiramatsu <mhiramat@redhat.com>,
	Jason Baron <jbaron@redhat.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3 v2] perf_event: fix race in perf_swevent_get_recursion_context()
Date: Tue, 19 Jan 2010 17:06:55 +0800	[thread overview]
Message-ID: <4B55762F.7010204@cn.fujitsu.com> (raw)
In-Reply-To: <1263890793.4283.639.camel@laptop>



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
> 
> NAK
> 

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
patchset

Thanks,
Xiao

  reply	other threads:[~2010-01-19  9:09 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-01-18 13:42 [PATCH 1/3] perf_event: fix race in perf_swevent_get_recursion_context() Xiao Guangrong
2010-01-18 13:44 ` [PATCH 2/3] perf_event: cleanup for event profile buffer operation Xiao Guangrong
2010-01-18 13:46   ` [PATCH 3/3] tracing/kprobe: cleanup unused return value of function Xiao Guangrong
2010-01-18 16:16     ` Masami Hiramatsu
2010-01-19  8:37     ` [PATCH 1/3 v2] perf_event: fix race in perf_swevent_get_recursion_context() Xiao Guangrong
2010-01-19  8:46       ` Peter Zijlstra
2010-01-19  9:06         ` Xiao Guangrong [this message]
2010-01-19  8:39     ` [PATCH 2/3 v2] perf_event: cleanup for event profile buffer operation Xiao Guangrong
2010-01-19  8:41     ` [PATCH 3/3 v2] tracing/kprobe: cleanup unused return value of function Xiao Guangrong
2010-01-18 16:21   ` [PATCH 2/3] perf_event: cleanup for event profile buffer operation Masami Hiramatsu
2010-01-18 17:20     ` Frederic Weisbecker
2010-01-18 17:48       ` Masami Hiramatsu
2010-01-18 18:02         ` Frederic Weisbecker
2010-01-19  1:26         ` Xiao Guangrong
2010-01-19  9:00           ` Frederic Weisbecker
2010-01-19 14:26             ` Masami Hiramatsu
2010-01-18 17:11   ` Frederic Weisbecker
2010-01-18 13:55 ` [PATCH 1/3] perf_event: fix race in perf_swevent_get_recursion_context() Peter Zijlstra
2010-01-19  7:36   ` Xiao Guangrong
2010-01-19  8:41     ` Peter Zijlstra
2010-01-18 16:41 ` Frederic Weisbecker
2010-01-19  1:19   ` Xiao Guangrong
2010-01-19  8:46     ` Peter Zijlstra
2010-01-19  8:58     ` Frederic Weisbecker
2010-01-19  9:09       ` Xiao Guangrong

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