From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
syzkaller <syzkaller@googlegroups.com>,
Kostya Serebryany <kcc@google.com>,
Alexander Potapenko <glider@google.com>,
Eric Dumazet <edumazet@google.com>,
Sasha Levin <sasha.levin@oracle.com>
Subject: Re: use-after-free in __perf_install_in_context
Date: Tue, 8 Dec 2015 19:57:38 +0100 [thread overview]
Message-ID: <20151208185737.GB3004@gmail.com> (raw)
In-Reply-To: <20151208162227.GB6357@twins.programming.kicks-ass.net>
* Peter Zijlstra <peterz@infradead.org> wrote:
> On Fri, Dec 04, 2015 at 09:04:35PM +0100, Dmitry Vyukov wrote:
> > Hello,
> >
> > While running syzkaller fuzzer I am seeing lots of the following
> > use-after-free reports. Unfortunately all my numerous attempts to
> > reproduce them in a controlled environment failed. They pop up during
> > fuzzing periodically (once in several hours in a single VM), but
> > whenever I try to stress-replay what happened in the VM before the
> > report, the use-after-free does not reproduce.
>
> Typical that :/
>
> > Can somebody knowledgeable in perf subsystem look at the report? Maybe
> > it is possible to figure out what happened based purely on the report.
> > I can pretty reliably test any proposed fixes.
>
> So I'm still going over the code, but meanwhile I tried reproducing this
> using the perf_fuzzer and some debug code, but no luck with that.
>
> Since you seem to be able to reproduce, could you do a run with the
> below patch in to see if it tickles something?
Btw., could we add more redundancy / debug code to the refcounting code? It seems
to be a frequent source of very hard to find/fix races/bugs - so it should be ripe
for some extra debug infrastructure ...
Thanks,
Ingo
next prev parent reply other threads:[~2015-12-08 18:57 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-04 20:04 use-after-free in __perf_install_in_context Dmitry Vyukov
2015-12-04 20:32 ` Alexei Starovoitov
2015-12-04 21:00 ` Dmitry Vyukov
2015-12-07 11:04 ` Dmitry Vyukov
2015-12-07 11:06 ` Dmitry Vyukov
2015-12-07 11:24 ` Dmitry Vyukov
2015-12-07 15:36 ` Peter Zijlstra
2015-12-07 16:09 ` Dmitry Vyukov
2015-12-08 3:24 ` Alexei Starovoitov
2015-12-08 16:12 ` Dmitry Vyukov
2015-12-08 17:54 ` Alexei Starovoitov
2015-12-08 17:56 ` Dmitry Vyukov
2015-12-08 18:05 ` Alexei Starovoitov
2015-12-08 18:35 ` Dmitry Vyukov
2015-12-08 19:56 ` Alexei Starovoitov
2015-12-09 9:17 ` Dmitry Vyukov
2015-12-10 3:54 ` Alexei Starovoitov
2015-12-10 9:02 ` Peter Zijlstra
2015-12-10 17:03 ` Alexei Starovoitov
2015-12-11 8:14 ` Ingo Molnar
2015-12-15 13:11 ` Dmitry Vyukov
2015-12-08 16:44 ` Peter Zijlstra
2015-12-08 19:14 ` Dmitry Vyukov
2015-12-10 19:57 ` Peter Zijlstra
2015-12-15 13:09 ` Dmitry Vyukov
2015-12-17 14:06 ` Peter Zijlstra
2015-12-17 14:08 ` Dmitry Vyukov
2015-12-17 14:26 ` Peter Zijlstra
2015-12-17 14:28 ` Peter Zijlstra
2015-12-17 14:35 ` Dmitry Vyukov
2015-12-17 14:43 ` Peter Zijlstra
2015-12-31 17:15 ` Dmitry Vyukov
2016-01-05 12:17 ` Peter Zijlstra
2016-01-08 8:40 ` Dmitry Vyukov
2016-01-08 10:28 ` Dmitry Vyukov
2016-01-06 18:46 ` [tip:perf/core] perf: Fix race in perf_event_exec() tip-bot for Peter Zijlstra
2016-01-06 18:56 ` Eric Dumazet
2016-01-07 13:40 ` Peter Zijlstra
2016-01-07 16:26 ` Paul E. McKenney
2016-01-07 16:36 ` Eric Dumazet
2016-01-07 16:46 ` Paul E. McKenney
2015-12-08 16:22 ` use-after-free in __perf_install_in_context Peter Zijlstra
2015-12-08 18:57 ` Ingo Molnar [this message]
2015-12-09 9:05 ` Peter Zijlstra
2015-12-08 16:27 ` Peter Zijlstra
2015-12-08 16:50 ` Dmitry Vyukov
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