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From: Dmitry Vyukov <dvyukov@google.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
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>
Subject: Re: INFO: rcu detected stall in ndisc_alloc_skb
Date: Mon, 31 Dec 2018 09:24:16 +0100	[thread overview]
Message-ID: <CACT4Y+YYwYDnqFmMwfSg6UNXnrbh46bo0jp7ijbej8nkDDmBXQ@mail.gmail.com> (raw)
In-Reply-To: <ef2508c9-d069-2143-09a6-a90b9ef12568@I-love.SAKURA.ne.jp>

On Mon, Dec 31, 2018 at 9:17 AM Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
>
> On 2018/12/31 16:49, Dmitry Vyukov wrote:
> > On Mon, Dec 31, 2018 at 8:42 AM syzbot
> > <syzbot+ea7d9cb314b4ab49a18a@syzkaller.appspotmail.com> wrote:
> >>
> >> Hello,
> >>
> >> syzbot found the following crash on:
> >>
> >> HEAD commit:    ef4ab8447aa2 selftests: bpf: install script with_addr.sh
> >> git tree:       bpf-next
> >> console output: https://syzkaller.appspot.com/x/log.txt?x=14a28b6e400000
> >> kernel config:  https://syzkaller.appspot.com/x/.config?x=7e7e2279c0020d5f
> >> dashboard link: https://syzkaller.appspot.com/bug?extid=ea7d9cb314b4ab49a18a
> >> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> >>
> >> Unfortunately, I don't have any reproducer for this crash yet.
> >>
> >> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> >> Reported-by: syzbot+ea7d9cb314b4ab49a18a@syzkaller.appspotmail.com
> >
> > 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.

  reply	other threads:[~2018-12-31  8:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-31  7:42 syzbot
2018-12-31  7:49 ` Dmitry Vyukov
2018-12-31  7:49   ` Dmitry Vyukov
2018-12-31  8:17   ` Tetsuo Handa
2018-12-31  8:24     ` Dmitry Vyukov [this message]
2018-12-31  8:24       ` Dmitry Vyukov
2019-01-02 17:06       ` Tetsuo Handa
2019-01-05 10:49         ` Tetsuo Handa
2019-01-06 13:24           ` Dmitry Vyukov
2019-01-06 13:24             ` Dmitry Vyukov
2019-01-06 13:47             ` Tetsuo Handa
2019-01-07 11:12               ` Dmitry Vyukov
2019-01-07 11:12                 ` Dmitry Vyukov
2019-01-18  5:20                 ` Tetsuo Handa
2019-01-19 12:16                   ` Dmitry Vyukov
2019-01-19 12:16                     ` Dmitry Vyukov
2019-01-19 13:10                     ` Tetsuo Handa
2019-01-20 13:30                       ` Dmitry Vyukov
2019-01-20 13:30                         ` Dmitry Vyukov
2019-01-20 14:24                         ` Tetsuo Handa

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