Subject: Re: WARNING: refcount bug in igmp_start_timer

From: syzbot <[email-masked]>
Date: Thu, 11 Apr 2019 23:44:01 -0700

syzbot has bisected this bug to:

commit fc5e9d63a8db40e9e3a3b180be33d44af8a3cee8
Author: Daniel Vetter <[email-masked]>
Date:   Wed May 24 14:52:05 2017 +0000

     drm/sti: Drop drm_vblank_cleanup

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=13f62c2d200000
start commit:   ae596de1 Compiler Attributes: naked can be shared
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=100e2c2d200000
console output: https://syzkaller.appspot.com/x/log.txt?x=17f62c2d200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5fa12be50bca08d8
dashboard link: https://syzkaller.appspot.com/bug?extid=e28037ac1c96d2a86e89
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=178537da400000

Reported-by: [email-masked]
Fixes: fc5e9d63a8db ("drm/sti: Drop drm_vblank_cleanup")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection