Messages in this thread | | | From | Dmitry Vyukov <> | Date | Mon, 17 Sep 2018 15:57:15 +0200 | Subject | Re: possible deadlock in blkdev_reread_part |
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On Thu, Sep 13, 2018 at 3:43 PM, Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> wrote: > On 2018/09/13 21:58, Dmitry Vyukov wrote: >> On Wed, May 2, 2018 at 1:23 PM, Dmitry Vyukov <dvyukov@google.com> wrote: >>> On Wed, May 2, 2018 at 12:30 PM, Tetsuo Handa >>> <penguin-kernel@i-love.sakura.ne.jp> wrote: >>>> Dmitry Vyukov wrote: >>>>>> syzbot is reporting various bugs which involve /dev/loopX. >>>>>> Two of them >>>>>> >>>>>> INFO: rcu detected stall in lo_ioctl >>>>>> https://syzkaller.appspot.com/bug?id=7b49fb610af9cca78c24e9f796f2e8b0d5573997 >>>>>> >>>>>> general protection fault in lo_ioctl (2) >>>>>> https://syzkaller.appspot.com/bug?id=f3cfe26e785d85f9ee259f385515291d21bd80a3 >>>>> >>>>> /\/\/\/\/\/\/\/\/\/\/\/\/\/\/\ >>>>> >>>>> Now there is a repro for this one. I've pushed it to kernel mailing lists: >>>>> >>>>> https://groups.google.com/d/msg/syzkaller-bugs/c8KUcTAzTvA/3o_7g6-tAwAJ >>>> >>>> OK, thanks. But among loop related reports, this will be a dup of >>>> "INFO: rcu detected stall in blkdev_ioctl" which already has C reproducer. >>>> Should we merge them? >>> >>> Yes, sure, I will take care of it. >> >> 1. I forgot to take care of it. >> >> 2. "INFO: rcu detected stall in blkdev_ioctl" was fixed 3 months ago: >> https://syzkaller.appspot.com/bug?id=1f7b710f4110f225aed1f4263ec2b98b8dbd472e >> >> but this bug still happens up until now: >> https://syzkaller.appspot.com/bug?id=bf154052f0eea4bc7712499e4569505907d15889 >> >> So this is a different bug. > > I'm not sure what you are talking about. > RCU stall and lockdep warning are obviously different bugs.
Ah, OK, I misinterpreted your "But among loop related reports, this will be a dup of "INFO: rcu detected stall in blkdev_ioctl"". So this is just an independent bug that still happens.
> Regarding lockdep warning on loop module, we are still waiting for Jens to > come up a better alternative than > http://lkml.kernel.org/r/1527297408-4428-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp . > Since no alternative was proposed, I think we should start testing my patch. >
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