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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Thu, 19 May 2022 13:01:25 +0200
Message-ID: <CACT4Y+Z9GUz7xK8YKuVewTEopCUWX9tCRhWZq3O84Lw-ZRXd+w@mail.gmail.com>
Subject: Re: [syzbot] KASAN: use-after-free Read in bio_poll
To:     syzbot <syzbot+99938118dfd9e1b0741a@syzkaller.appspotmail.com>,
        syzkaller-bugs@googlegroups.com
Cc:     linux-kernel@vger.kernel.org
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On Tue, 10 May 2022 at 14:45, Jens Axboe <axboe@kernel.dk> wrote:
>
> On 5/9/22 11:50 PM, Christoph Hellwig wrote:
> > On Tue, May 10, 2022 at 08:13:58AM +0800, Ming Lei wrote:
> >>> Guys, should we just queue:
> >>>
> >>> ommit 9650b453a3d4b1b8ed4ea8bcb9b40109608d1faf
> >>> Author: Ming Lei <ming.lei@redhat.com>
> >>> Date:   Wed Apr 20 22:31:10 2022 +0800
> >>>
> >>>     block: ignore RWF_HIPRI hint for sync dio
> >>>
> >>> up for 5.18 and stable?
> >>
> >> I am fine with merging to 5.18 & stable.
> >
> > I'm fine, too.  But are we sure this actually is one and the same
> > issue?  Otherwise I'll try to find some time to feed it to syzbot
> > first.
>
> I re-wrote the reproducer a bit and can reproduce it, so I can certainly
> test a backport. But yes, I was skeptical on this being the same issue
> too. My initial reaction was that this is likely due to the bio being
> "downgraded" from polled to IRQ driven, and hence completes without an
> extra reference before the bio_poll() is done on it. Which is not the
> issue described in the referenced commit.

#syz fix: block: ignore RWF_HIPRI hint for sync dio