lkml.org 
[lkml]   [2019]   [Dec]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: INFO: task hung in sync_inodes_sb (3)
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

\
 
 \ /
  Last update: 2019-12-27 05:47    [W:0.034 / U:8.060 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site