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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: Sun, 6 Jan 2019 14:24:23 +0100	[thread overview]
Message-ID: <CACT4Y+Y5cdD=optF2k4a0W7vriVnzmzLU0SPGEJoOHRMi_bsZA@mail.gmail.com> (raw)
In-Reply-To: <8cdbcb63-d2f7-cace-0eda-d73255fd47e7@i-love.sakura.ne.jp>

On Sat, Jan 5, 2019 at 11:49 AM Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
>
> On 2019/01/03 2:06, Tetsuo Handa wrote:
> > 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
> >
>
> A report at 2019/01/05 10:08 from "no output from test machine (2)"
> ( https://syzkaller.appspot.com/text?tag=CrashLog&x=1700726f400000 )
> says that there are flood of memory allocation failure messages.
> Since continuous memory allocation failure messages itself is not
> recognized as a crash, we might be misunderstanding that this problem
> is not occurring recently. It will be nice if we can run testcases
> which are executed on bpf-next tree.

What exactly do you mean by running test cases on bpf-next tree?
syzbot tests bpf-next, so it executes lots of test cases on that tree.
One can also ask for patch testing on bpf-next tree to test a specific
test case.

  reply	other threads:[~2019-01-06 13:24 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
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 [this message]
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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