syzbot has bisected this bug to: commit fb041bb7c0a918b95c6889fc965cdc4a75b4c0ca Author: Will Deacon <will@xxxxxxxxxx> Date: Thu Nov 21 11:59:00 2019 +0000 locking/refcount: Consolidate implementations of refcount_t bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=117e9e91e00000 start commit: 2c523b34 Linux 5.6-rc5 git tree: upstream final crash: https://syzkaller.appspot.com/x/report.txt?x=137e9e91e00000 console output: https://syzkaller.appspot.com/x/log.txt?x=157e9e91e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=a5295e161cd85b82 dashboard link: https://syzkaller.appspot.com/bug?extid=cea71eec5d6de256d54d syz repro: https://syzkaller.appspot.com/x/repro.syz?x=164b5181e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=166dd70de00000 Reported-by: syzbot+cea71eec5d6de256d54d@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: fb041bb7c0a9 ("locking/refcount: Consolidate implementations of refcount_t") For information about bisection process see: https://goo.gl/tpsmEJ#bisection