From: Ming Lei <ming.lei@redhat.com>
To: syzbot <syzbot+2b9e54155c8c25d8d165@syzkaller.appspotmail.com>
Cc: akpm@linux-foundation.org, axboe@kernel.dk, dave@stgolabs.net,
hch@lst.de, hughd@google.com, ktkhai@virtuozzo.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
mhocko@suse.com, osandov@fb.com, syzkaller-bugs@googlegroups.com
Subject: Re: INFO: task hung in sync_inodes_sb (3)
Date: Fri, 27 Dec 2019 12:46:00 +0800 [thread overview]
Message-ID: <20191227044600.GA9220@ming.t460p> (raw)
In-Reply-To: <0000000000002b326d059aa295e9@google.com>
On Thu, Dec 26, 2019 at 02:06:01PM -0800, syzbot wrote:
> syzbot has bisected this bug to:
>
> commit 6dc4f100c175dd0511ae8674786e7c9006cdfbfa
> Author: Ming Lei <ming.lei@redhat.com>
> Date: Fri Feb 15 11:13:19 2019 +0000
>
> block: allow bio_for_each_segment_all() to iterate over multi-page bvec
>
> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1674423ee00000
> start commit: 46cf053e Linux 5.5-rc3
> git tree: upstream
> final crash: https://syzkaller.appspot.com/x/report.txt?x=1574423ee00000
> console output: https://syzkaller.appspot.com/x/log.txt?x=1174423ee00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=ed9d672709340e35
> dashboard link: https://syzkaller.appspot.com/bug?extid=2b9e54155c8c25d8d165
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=152bdc56e00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159c489ee00000
>
> Reported-by: syzbot+2b9e54155c8c25d8d165@syzkaller.appspotmail.com
> Fixes: 6dc4f100c175 ("block: allow bio_for_each_segment_all() to iterate
> over multi-page bvec")
Looks this syzbot test triggers bio truncate(guard_bio_eod()), and the
truncated bytes is bigger than the last bvec, which length is overflowed
by 'bvec->bv_len -= truncated_bytes'.
Finally bio_for_each_segment_all() trigger the issue.
Will figure out one patch to fix it.
Thanks,
Ming
prev parent reply other threads:[~2019-12-27 4:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-26 21:25 INFO: task hung in sync_inodes_sb (3) syzbot
2019-12-26 22:06 ` syzbot
2019-12-27 4:46 ` Ming Lei [this message]
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