From: Dmitry Vyukov <dvyukov@google.com>
To: Ingo Molnar <mingo@kernel.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
syzkaller <syzkaller@googlegroups.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
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, 15 Dec 2015 14:11:12 +0100 [thread overview]
Message-ID: <CACT4Y+YUkYgCuQFW6eBTtdfRqdF7EEtrB3VaYJk+LUXE_-iGRQ@mail.gmail.com> (raw)
In-Reply-To: <20151211081433.GB21600@gmail.com>
On Fri, Dec 11, 2015 at 9:14 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
>> On Thu, Dec 10, 2015 at 10:02:51AM +0100, Peter Zijlstra wrote:
>> > On Wed, Dec 09, 2015 at 07:54:35PM -0800, Alexei Starovoitov wrote:
>> > > Freeing memory is a requirement regardless.
>> > > Even when kernel running with kasan, there must be a way to stop
>> > > stack collection and free that memory.
>> > > You cannot treat kernel as your test program or 'device under test'.
>> >
>> > Relax, that is exactly what lockdep does. It cannot dynamically allocate
>> > things because allocators use lock etc..
>> >
>> > Its fine to build up state for debug bits, esp. if its bounded, like the
>> > number of unique callchains.
>>
>> except the code in question is doing unbounded alloc_pages()
>
> Yes, but the trick is to still have a bound sized debug pool - which runs out of
> entries gracefully.
>
> Which in practice is plenty enough for most types of testing, and is a lot more
> robust than any dynamic scheme.
A hard upper bound on consumed memory would work for us without
introducing any slowdown and without increasing code complexity. So it
sounds good to me.
next prev parent reply other threads:[~2015-12-15 13:11 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 [this message]
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
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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