Re: WARNING in cgroup_exit

[syzbot]

syzbot has bisected this bug to:

commit e42940e8559c8bbffa8286cc78067c75eb42b374
Author: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Date:   Tue May 7 01:03:30 2019 +0000

    Merge remote-tracking branch 'rdma/for-next'

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1746b4e8a00000
start commit:   00c3bc00 Add linux-next specific files for 20190507
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=14c6b4e8a00000
console output: https://syzkaller.appspot.com/x/log.txt?x=10c6b4e8a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=63cd766601c6c9fc
dashboard link: https://syzkaller.appspot.com/bug?extid=f14868630901fc6151d3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=10fcf758a00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1202ffa4a00000

Reported-by: syzbot+f14868630901fc6151d3@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: e42940e8559c ("Merge remote-tracking branch 'rdma/for-next'")

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