From: Dmitry Vyukov <dvyukov@google.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Michal Hocko <mhocko@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
syzkaller <syzkaller@googlegroups.com>,
Kostya Serebryany <kcc@google.com>,
Alexander Potapenko <glider@google.com>,
Sasha Levin <sasha.levin@oracle.com>,
Eric Dumazet <edumazet@google.com>,
Greg Thelen <gthelen@google.com>, Tejun Heo <tj@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: WARNING in handle_mm_fault
Date: Wed, 25 Nov 2015 14:08:41 +0100 [thread overview]
Message-ID: <CACT4Y+Zn+mK37-mvqDQTyt1Psp6HT2heT0e937SO24F7V1q7PA@mail.gmail.com> (raw)
In-Reply-To: <565592A1.50407@I-love.SAKURA.ne.jp>
On Wed, Nov 25, 2015 at 11:51 AM, Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
> On 2015/11/25 17:44, Michal Hocko wrote:
>> Sasha has reported the same thing some time ago
>> http://www.spinics.net/lists/cgroups/msg14075.html. Tejun had a theory
>> http://www.spinics.net/lists/cgroups/msg14078.html but we never got down
>> to the solution.
>
> Did you check assembly code?
> https://gcc.gnu.org/ml/gcc/2012-02/msg00005.html
If the race described in
http://www.spinics.net/lists/cgroups/msg14078.html does actually
happen, then there is nothing to check.
https://gcc.gnu.org/ml/gcc/2012-02/msg00005.html talks about different
memory locations, if there is store-widening involving different
memory locations, then this is a compiler bug. But the race happens on
a single memory location, in such case the code is buggy.
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next prev parent reply other threads:[~2015-11-25 13:09 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-24 13:50 Dmitry Vyukov
2015-11-24 22:31 ` Johannes Weiner
2015-11-25 13:05 ` Dmitry Vyukov
2015-11-25 13:12 ` Dmitry Vyukov
2015-11-25 8:44 ` Michal Hocko
2015-11-25 10:51 ` Tetsuo Handa
2015-11-25 13:08 ` Dmitry Vyukov [this message]
2015-11-25 15:27 ` Tetsuo Handa
2015-11-25 17:21 ` Dmitry Vyukov
2015-11-25 17:32 ` Dmitry Vyukov
2015-11-25 17:37 ` Michal Hocko
2015-11-25 17:44 ` Dmitry Vyukov
2015-11-26 11:33 ` Tetsuo Handa
2015-11-30 16:20 ` Peter Zijlstra
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