From: Sasha Levin <sasha.levin@oracle.com>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: ast@kernel.org, "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>, Tejun Heo <tj@kernel.org>
Subject: Re: bpf: use-after-free in array_map_alloc
Date: Sun, 17 Apr 2016 18:45:44 -0400 [thread overview]
Message-ID: <57141218.4000103@oracle.com> (raw)
In-Reply-To: <20160417172943.GA83672@ast-mbp.thefacebook.com>
On 04/17/2016 01:29 PM, Alexei Starovoitov wrote:
> On Sun, Apr 17, 2016 at 12:58:21PM -0400, Sasha Levin wrote:
>> > Hi all,
>> >
>> > I've hit the following while fuzzing with syzkaller inside a KVM tools guest
>> > running the latest -next kernel:
> thanks for the report. Adding Tejun...
> if I read the report correctly it's not about bpf, but rather points to
> the issue inside percpu logic.
> First __alloc_percpu_gfp() is called, then the memory is freed with
> free_percpu() which triggers async pcpu_balance_work and then
> pcpu_extend_area_map is hitting use-after-free.
> I guess bpf percpu array map is stressing this logic the most.
> Any simpler steps to reproduce ?
No simple way to reproduce. I blamed bpf because I saw a few traces
and it was only bpf that was causing it, there was no other reasoning
behind it.
Thanks,
Sasha
next prev parent reply other threads:[~2016-04-17 22:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-17 16:58 bpf: use-after-free in array_map_alloc Sasha Levin
2016-04-17 17:29 ` Alexei Starovoitov
2016-04-17 22:45 ` Sasha Levin [this message]
2016-05-23 12:01 ` Vlastimil Babka
2016-05-23 12:07 ` Vlastimil Babka
2016-05-23 21:35 ` Tejun Heo
2016-05-23 22:13 ` Alexei Starovoitov
2016-05-24 8:40 ` Vlastimil Babka
2016-05-24 15:30 ` Tejun Heo
2016-05-24 19:04 ` Tejun Heo
2016-05-24 20:43 ` Alexei Starovoitov
2016-05-25 15:44 ` [PATCH percpu/for-4.7-fixes 1/2] percpu: fix synchronization between chunk->map_extend_work and chunk destruction Tejun Heo
2016-05-26 9:19 ` Vlastimil Babka
2016-05-26 19:21 ` Tejun Heo
2016-05-26 20:48 ` Vlastimil Babka
2016-05-25 15:45 ` [PATCH percpu/for-4.7-fixes 2/2] percpu: fix synchronization between synchronous map extension " Tejun Heo
2016-05-26 9:48 ` Vlastimil Babka
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