From: Linus Torvalds <torvalds@linux-foundation.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Manfred Spraul <manfred@colorfullife.com>,
Oleg Nesterov <oleg@redhat.com>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [RFC][PATCH] sched: Fix TASK_DEAD race in finish_task_switch()
Date: Tue, 29 Sep 2015 13:41:50 -0400 [thread overview]
Message-ID: <CA+55aFy6j3YFF6vZDgT4cX62L02bqRBDDx0MaR+qT-rmG+a0wA@mail.gmail.com> (raw)
In-Reply-To: <20150929165031.GU3816@twins.programming.kicks-ass.net>
On Tue, Sep 29, 2015 at 12:50 PM, Peter Zijlstra <peterz@infradead.org> wrote:
>
> The control dependency creates a LOAD->STORE order, that is, no STOREs
> can happen until we observe !p->on_cpu.
Fair enough.
> Right, but wmb isn't sufficient as it doesn't order the prev->state LOAD
> vs the prev->on_cpu = 0 STORE. If those happen in the wrong order the
> described race can happen and we get a use-after-free.
.. and you convinced me. The patch is good. Ack.
Linus
next prev parent reply other threads:[~2015-09-29 17:42 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-29 12:45 [RFC][PATCH] sched: Fix TASK_DEAD race in finish_task_switch() Peter Zijlstra
2015-09-29 16:40 ` Linus Torvalds
2015-09-29 16:50 ` Peter Zijlstra
2015-09-29 17:41 ` Linus Torvalds [this message]
2015-10-06 16:12 ` [tip:sched/core] sched/core: " tip-bot for Peter Zijlstra
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