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From: Andrew Morton <akpm@linux-foundation.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>, Oleg Nesterov <oleg@redhat.com>,
	"Sylvain 'ythier' Hitier" <sylvain.hitier@gmail.com>,
	linux-kernel@vger.kernel.org,
	Vince Weaver <vincent.weaver@maine.edu>
Subject: Re: [PATCH] fork.c: copy_process(): fix cleanup WRT perf_event_free_task()
Date: Wed, 1 Oct 2014 15:44:58 -0700	[thread overview]
Message-ID: <20141001154458.a3c4bfa7ef000ecc1fc7c5de@linux-foundation.org> (raw)
In-Reply-To: <20140929140048.GK5430@worktop>

On Mon, 29 Sep 2014 16:00:48 +0200 Peter Zijlstra <peterz@infradead.org> wrote:

> On Mon, Sep 29, 2014 at 02:07:22PM +0200, Ingo Molnar wrote:
> > 
> > * Peter Zijlstra <peterz@infradead.org> wrote:
> > 
> > > Subject: perf: Fix perf bug in fork()
> > > 
> > > Oleg noticed that a cleanup by Sylvain actually uncovered a bug; by
> > > calling perf_event_free_task() when failing sched_fork() we will not yet
> > > have done the memset() on ->perf_event_ctxp[] and will therefore try and
> > > 'free' the inherited contexts, which are still in use by the parent
> > > process. This is bad..
> > > 
> > > Suggested-by: Oleg Nesterov <oleg@redhat.com>
> > > Reported-by: Oleg Nesterov <oleg@redhat.com>
> > > Reported-by: Sylvain 'ythier' Hitier <sylvain.hitier@gmail.com>
> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > 
> > Could this fix a couple of fuzzer triggered perf crashes perhaps?
> 
> It could indeed I suppose.. you never know what paths those fuzzers
> manage to hit.

The patch isn't in linux-next and didn't cc stable.  I think I'll
squirt it Linuswards later this week unless someone stops me..


  reply	other threads:[~2014-10-01 22:45 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-26 21:06 [PATCH] fork.c: copy_process(): fix cleanup WRT perf_event_free_task() Sylvain 'ythier' Hitier
2014-09-27 18:07 ` Oleg Nesterov
2014-09-29 10:12   ` Peter Zijlstra
2014-09-29 12:07     ` Ingo Molnar
2014-09-29 14:00       ` Peter Zijlstra
2014-10-01 22:44         ` Andrew Morton [this message]
2014-09-29 22:28     ` Oleg Nesterov
2014-10-03  5:27     ` [tip:perf/urgent] perf: Fix perf bug in fork() tip-bot for Peter Zijlstra

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