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From: Xunlei Pang <xpang@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, Juri Lelli <juri.lelli@arm.com>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] sched/deadline/rtmutex: Fix a PI crash for deadline tasks
Date: Wed, 13 Apr 2016 10:13:19 +0800	[thread overview]
Message-ID: <570DAB3F.4030501@redhat.com> (raw)
In-Reply-To: <20160412155149.GJ1087@worktop>

On 2016/04/12 at 23:51, Peter Zijlstra wrote:
> On Tue, Apr 12, 2016 at 11:08:04AM +0800, Xunlei Pang wrote:
>> I spotted another issue, we access pi_task without any lock in enqueue_task_dl(),
> OK, so I'm on the road and entirely jetlagged, but how can
> enqueue_task_dl() not have rq->lock held?

It held current's rq->lock, but not holding pi_task's any lock, so pi_task's attributes
can change concurrently with subsequent pi_se->dl_runtime and pi_se->dl_period
access, and result in issues.

Regards,
Xunlei

      reply	other threads:[~2016-04-13  2:13 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-01 11:00 [PATCH] sched/deadline/rtmutex: Fix a PI crash for deadline tasks Xunlei Pang
2016-04-01 11:38 ` Peter Zijlstra
2016-04-01 12:23   ` Xunlei Pang
2016-04-01 13:12     ` Peter Zijlstra
2016-04-01 13:34       ` Xunlei Pang
2016-04-01 21:51         ` Peter Zijlstra
2016-04-02 10:19           ` Xunlei Pang
2016-04-05  8:38           ` Xunlei Pang
2016-04-05  9:19             ` Peter Zijlstra
2016-04-05  9:29               ` Peter Zijlstra
2016-04-05 10:48                 ` Xunlei Pang
2016-04-05 11:32                   ` Peter Zijlstra
2016-04-08 16:25                 ` Steven Rostedt
2016-04-08 17:38                   ` Peter Zijlstra
2016-04-08 18:50                     ` Steven Rostedt
2016-04-08 18:59                       ` Peter Zijlstra
2016-04-08 19:15                         ` Steven Rostedt
2016-04-08 19:28                           ` Steven Rostedt
2016-04-09  3:27                             ` Xunlei Pang
2016-04-09  3:25                         ` Xunlei Pang
2016-04-09 13:29                           ` Peter Zijlstra
2016-04-10  8:22                             ` Xunlei Pang
2016-04-12  3:08                               ` Xunlei Pang
2016-04-12 15:51                                 ` Peter Zijlstra
2016-04-13  2:13                                   ` Xunlei Pang [this message]

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