Re: WARNING in cbq_destroy_class

[syzbot]

syzbot has bisected this bug to:

commit d51aae68b142f48232257e96ce317db25445418d
Author: Jiri Pirko <jiri@xxxxxxxxxxxx>
Date:   Mon Nov 27 17:37:21 2017 +0000

    net: sched: cbq: create block for q->link.block

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=12efb80de00000
start commit:   80892772 hsr: Fix a compilation error
git tree:       net
final crash:    https://syzkaller.appspot.com/x/report.txt?x=11efb80de00000
console output: https://syzkaller.appspot.com/x/log.txt?x=16efb80de00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d9290aeb7e6cf1c4
dashboard link: https://syzkaller.appspot.com/bug?extid=0a0596220218fcb603a8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11f107d1e00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12114335e00000

Reported-by: syzbot+0a0596220218fcb603a8@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: d51aae68b142 ("net: sched: cbq: create block for q->link.block")

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