On Sat, Dec 15, 2018 at 9:34 PM syzbot <syzbot+9c69c282adc4edd2b540@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > > syzbot has found a reproducer for the following crash on: > > HEAD commit: d14b746c6c1c Add linux-next specific files for 20181214 > git tree: linux-next > console output: https://syzkaller.appspot.com/x/log.txt?x=143f9a15400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=1da6d2d18f803140 > dashboard link: https://syzkaller.appspot.com/bug?extid=9c69c282adc4edd2b540 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12a6e543400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+9c69c282adc4edd2b540@xxxxxxxxxxxxxxxxxxxxxxxxx > > overlayfs: filesystem on './file0' not supported as upperdir > overlayfs: filesystem on './file0' not supported as upperdir > overlayfs: filesystem on './file0' not supported as upperdir > overlayfs: filesystem on './file0' not supported as upperdir > overlayfs: filesystem on './file0' not supported as upperdir > WARNING: CPU: 1 PID: 28918 at fs/overlayfs/dir.c:263 > ovl_instantiate+0x369/0x400 fs/overlayfs/dir.c:263 Looks like some corner case race when using same dir as upper and lower. Doesn't look like a critical issue, I just don't know how to explain getting to this state. Couldn't reproduce on my target machine. It would have been interesting for me to see the strace of the repro threads when that WARN happens. I wonder if anyone else has already asked for it and how hard would it be to make that information available with the bug report. Thanks, Amir.
