David, On Sun, Dec 01, 2019 at 10:45:08PM -0800, syzbot wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: b94ae8ad Merge tag 'seccomp-v5.5-rc1' of git://git.kernel... > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1387ab12e00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ff560c3de405258c > dashboard link: https://syzkaller.appspot.com/bug?extid=d37abaade33a934f16f2 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12945c41e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=161e202ee00000 > > The bug was bisected to: > > commit 8cefc107ca54c8b06438b7dc9cc08bc0a11d5b98 > Author: David Howells <dhowells@xxxxxxxxxx> > Date: Fri Nov 15 13:30:32 2019 +0000 > > pipe: Use head and tail pointers for the ring, not cursor and length > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=118cce96e00000 > final crash: https://syzkaller.appspot.com/x/report.txt?x=138cce96e00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=158cce96e00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+d37abaade33a934f16f2@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 8cefc107ca54 ("pipe: Use head and tail pointers for the ring, not > cursor and length") > > ------------[ cut here ]------------ > kernel BUG at fs/pipe.c:582! This same BUG_ON() crashed my system during normal use, no syzkaller involved at all, on mainline 937d6eefc7. Can you please take a look? This syzbot report has a reproducer so that might be the easiest place to start. - Eric
