From: Ming Lei <ming.lei@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: syzbot <syzbot+fd15ff734dace9e16437@syzkaller.appspotmail.com>,
bcrl@kvack.org, hch@lst.de, linux-aio@kvack.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, tj@kernel.org,
viro@zeniv.linux.org.uk, vkabatov@redhat.com
Subject: Re: general protection fault in percpu_ref_exit
Date: Fri, 9 Oct 2020 12:05:25 +0800 [thread overview]
Message-ID: <20201009040525.GB27356@T590> (raw)
In-Reply-To: <165db20c-bfc5-fca8-1ecf-45d85ea5d9e2@kernel.dk>
On Thu, Oct 08, 2020 at 07:23:02PM -0600, Jens Axboe wrote:
> On 10/8/20 2:28 PM, syzbot wrote:
> > syzbot has bisected this issue to:
> >
> > commit 2b0d3d3e4fcfb19d10f9a82910b8f0f05c56ee3e
> > Author: Ming Lei <ming.lei@redhat.com>
> > Date: Thu Oct 1 15:48:41 2020 +0000
> >
> > percpu_ref: reduce memory footprint of percpu_ref in fast path
> >
> > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=126930d0500000
> > start commit: 8b787da7 Add linux-next specific files for 20201007
> > git tree: linux-next
> > final oops: https://syzkaller.appspot.com/x/report.txt?x=116930d0500000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=166930d0500000
> > kernel config: https://syzkaller.appspot.com/x/.config?x=aac055e9c8fbd2b8
> > dashboard link: https://syzkaller.appspot.com/bug?extid=fd15ff734dace9e16437
> > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=119a0568500000
> > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=106c0a8b900000
> >
> > Reported-by: syzbot+fd15ff734dace9e16437@syzkaller.appspotmail.com
> > Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> Ming, this looks like a call of percpu_ref_exit() on a zeroed refs (that
> hasn't been initialized). Really a caller error imho, but might make sense
> to be a bit safer there.
Hello Jens,
The fix is sent out as:
https://lore.kernel.org/linux-block/20201009040356.43802-1-ming.lei@redhat.com/T/#u
Sorry for making the trouble.
Thanks,
Ming
prev parent reply other threads:[~2020-10-09 4:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 15:09 general protection fault in percpu_ref_exit syzbot
2020-10-08 20:28 ` syzbot
2020-10-09 1:23 ` Jens Axboe
2020-10-09 4:05 ` Ming Lei [this message]
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