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Subject: Re: INFO: rcu detected stall in ndisc_alloc_skb
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From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
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Date: Thu, 3 Jan 2019 02:06:58 +0900
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To: Dmitry Vyukov <dvyukov@google.com>
Cc: syzbot <syzbot+ea7d9cb314b4ab49a18a@syzkaller.appspotmail.com>, David Miller <davem@davemloft.net>, Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>, LKML <linux-kernel@vger.kernel.org>, netdev <netdev@vger.kernel.org>, syzkaller-bugs <syzkaller-bugs@googlegroups.com>, Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org>, Linux-MM <linux-mm@kvack.org>

On 2018/12/31 17:24, Dmitry Vyukov wrote:
>>> Since this involves OOMs and looks like a one-off induced memory corruption:
>>>
>>> #syz dup: kernel panic: corrupted stack end in wb_workfn
>>>
>>
>> Why?
>>
>> RCU stall in this case is likely to be latency caused by flooding of printk().
> 
> Just a hypothesis. OOMs lead to arbitrary memory corruptions, so can
> cause stalls as well. But can be what you said too. I just thought
> that cleaner dashboard is more useful than a large assorted pile of
> crashes. If you think it's actionable in some way, feel free to undup.
> 

We don't know why bpf tree is hitting this problem.
Let's continue monitoring this problem.

#syz undup