On Sun 20-05-18 23:07:02, syzbot wrote: > syzbot has found a reproducer for the following crash on: > > HEAD commit: 771c577c23ba Linux 4.17-rc6 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=108c9f37800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=982e2df1b9e60b02 > dashboard link: https://syzkaller.appspot.com/bug?extid=9a44753ac327c557796a > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1655584f800000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15134357800000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+9a44753ac327c557796a@xxxxxxxxxxxxxxxxxxxxxxxxx > > WARNING: CPU: 0 PID: 4577 at fs/ext4/inode.c:3894 > ext4_set_page_dirty+0x28d/0x330 fs/ext4/inode.c:3894 > Kernel panic - not syncing: panic_on_warn set ... Looking at the reproducer, this is the issue we have been speaking about at LSF/MM - direct IO read dirties pages after writeback has written them out and so we don't expect them to be dirtied. If someone told me I would not believe this is possible to hit by fuzzing ;) Good job from the syzkaller guys! Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
