On 10/8/20 2:28 PM, syzbot wrote: > syzbot has bisected this issue to: > > commit 2b0d3d3e4fcfb19d10f9a82910b8f0f05c56ee3e > Author: Ming Lei <ming.lei@xxxxxxxxxx> > Date: Thu Oct 1 15:48:41 2020 +0000 > > percpu_ref: reduce memory footprint of percpu_ref in fast path > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=126930d0500000 > start commit: 8b787da7 Add linux-next specific files for 20201007 > git tree: linux-next > final oops: https://syzkaller.appspot.com/x/report.txt?x=116930d0500000 > console output: https://syzkaller.appspot.com/x/log.txt?x=166930d0500000 > kernel config: https://syzkaller.appspot.com/x/.config?x=aac055e9c8fbd2b8 > dashboard link: https://syzkaller.appspot.com/bug?extid=fd15ff734dace9e16437 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=119a0568500000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=106c0a8b900000 > > Reported-by: syzbot+fd15ff734dace9e16437@xxxxxxxxxxxxxxxxxxxxxxxxx > Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection Ming, this looks like a call of percpu_ref_exit() on a zeroed refs (that hasn't been initialized). Really a caller error imho, but might make sense to be a bit safer there. -- Jens Axboe
