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Subject: Re: INFO: task hung in __blkdev_get
From:   Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
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Date:   Sun, 15 Apr 2018 00:26:54 +0900
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OK. The patch was sent to linux.git as commit 1e047eaab3bb5564.

#syz fix: block/loop: fix deadlock after loop_set_status

Dmitry Vyukov <dvyukov@google.com>" wrote:
> On Tue, Apr 10, 2018 at 3:04 PM, Tetsuo Handa
> <penguin-kernel@i-love.sakura.ne.jp> wrote:
> > Dmitry Vyukov wrote:
> >> On Tue, Apr 10, 2018 at 12:55 PM, Tetsuo Handa
> >> <penguin-kernel@i-love.sakura.ne.jp> wrote:
> >> > Hello.
> >> >
> >> > Since syzbot is reporting so many hung up bug which involves /dev/loopX ,
> >> > is it possible to "temporarily" apply below patch for testing under syzbot
> >>
> >> Unfortunately it's not possible, for full explanation please see:
> >> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#no-custom-patches
> >>
> >
> > I mean, sending custom patch to linux.git for -rc and revert the custom patch
> > before -final is released. It won't take so much period until we get the result.
> 
> Ah, I see, then I guess it wasn't a question to me.
> 
I noticed that there already is the lockdep report at

  possible deadlock in blkdev_reread_part
  https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889

entry, and no patch is proposed yet:

  https://groups.google.com/forum/#!msg/syzkaller-bugs/2Rw8-OM6IbM/SI4DyK-1AQAJ