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From: Ingo Molnar <mingo@kernel.org>
To: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Leo Yan <leo.yan@linaro.org>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] sched: fix tsk->pi_lock isn't held when do_set_cpus_allowed()
Date: Tue, 25 Aug 2015 10:30:59 +0200	[thread overview]
Message-ID: <20150825083059.GA20801@gmail.com> (raw)
In-Reply-To: <BLU436-SMTP1299386265B1F48065C898780610@phx.gbl>


* Wanpeng Li <wanpeng.li@hotmail.com> wrote:

> >>--- a/kernel/cpuset.c
> >>+++ b/kernel/cpuset.c
> >>@@ -2376,8 +2376,12 @@ void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
> >>  void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
> >>  {
> >>+	unsigned long flags;
> >>+
> >>  	rcu_read_lock();
> >>+	raw_spin_lock_irqsave(&tsk->pi_lock, flags);
> >>  	do_set_cpus_allowed(tsk, task_cs(tsk)->effective_cpus);
> >>+	raw_spin_lock_irqsave(&tsk->pi_lock, flags);
> >Just curious, Will introduce deadlock after acquire lock twice? ;)
> 
> Could you point out where acquires lock twice?

In the code you quote?

Thanks,

	Ingo

  reply	other threads:[~2015-08-25  8:31 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-25  7:59 [PATCH] sched: fix tsk->pi_lock isn't held when do_set_cpus_allowed() Wanpeng Li
2015-08-25  8:13 ` Leo Yan
2015-08-25  8:24   ` Wanpeng Li
2015-08-25  8:30     ` Ingo Molnar [this message]
2015-08-25  8:38       ` Wanpeng Li
2015-08-25 10:05 ` Peter Zijlstra
2015-08-25 10:10   ` Peter Zijlstra
2015-08-25 10:32     ` Peter Zijlstra
     [not found]       ` <BLU437-SMTP7261DF7A82716F49242C7B80610@phx.gbl>
2015-08-27 22:18         ` Peter Zijlstra
2015-08-28  1:49           ` Wanpeng Li
2015-08-25 10:18   ` Wanpeng Li
2015-08-27 13:47 ` T. Zhou
  -- strict thread matches above, loose matches on Subject: below --
2015-08-25  7:56 Wanpeng Li

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