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Date: Mon, 1 Dec 2014 10:43:24 -0800
From: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
To: lizf@kernel.org
Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org,
        Cong Wang <cwang@twopensource.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Paul Mackerras <paulus@samba.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>, Zefan Li <lizefan@huawei.com>
Subject: Re: [PATCH 3.4 43/91] perf: Fix a race condition in
 perf_remove_from_context()
Message-ID: <20141201184324.GA5032@us.ibm.com>
References: <1417077368-9217-1-git-send-email-lizf@kernel.org>
 <1417077794-9299-43-git-send-email-lizf@kernel.org>
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lizf@kernel.org [lizf@kernel.org] wrote:
| From: Cong Wang <cwang@twopensource.com>
| 
| 3.4.105-rc1 review patch.  If anyone has any objections, please let me know.
| 
<snip>
| 
| diff --git a/kernel/events/core.c b/kernel/events/core.c
| index 685ce46..c958be1 100644
| --- a/kernel/events/core.c
| +++ b/kernel/events/core.c
| @@ -1702,6 +1702,16 @@ retry:
|  	 */
|  	if (ctx->is_active) {
|  		raw_spin_unlock_irq(&ctx->lock);
| +		/*
| +		 * Reload the task pointer, it might have been changed by
| +		 * a concurrent perf_event_context_sched_out().
| +		 */
| +		task = ctx->task;
| +		/*
| +		 * Reload the task pointer, it might have been changed by
| +		 * a concurrent perf_event_context_sched_out().
| +		 */
| +		task = ctx->task;

Something wrong in the way the patch was applied ?
The lines are identical...

The original commit, 3577af70, has the change applied in two
places: perf_event_disable() and perf_remove_from_context().

|  		goto retry;
|  	}
| 
| -- 
| 1.9.1
| 
| --
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