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Date:   Tue, 7 Nov 2017 11:32:57 -0800
From:   Tejun Heo <tj@kernel.org>
To:     Shaohua Li <shli@fb.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, Jens Axboe <axboe@kernel.dk>,
        Andrew Morton <akpm@linux-foundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH V2] kthread: zero the kthread data structure
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References: <e00c78e6161ef7759a7e5f6abd2db84b9bcc8cf4.1510081552.git.shli@fb.com>
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On Tue, Nov 07, 2017 at 11:09:50AM -0800, Shaohua Li wrote:
> kthread() could bail out early before we initialize blkcg_css (if the
> kthread is killed very early. Please see xchg() statement in kthread()),
> which confuses free_kthread_struct. Instead of moving the blkcg_css
> initialization early, we simply zero the whole 'self' data structure,
> which doesn't sound much overhead.
> 
> Reported-by: syzbot <syzkaller@googlegroups.com>
> Fixes: 05e3db95ebfc ("kthread: add a mechanism to store cgroup info")
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Signed-off-by: Shaohua Li <shli@fb.com>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

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