From: Cong Wang <xiyou.wangc...@gmail.com>
Date: Thu, 12 Sep 2019 10:22:30 -0700
> When tcf_block_get() fails in sfb_init(), q->qdisc is still a NULL
> pointer which leads to a crash in sfb_destroy(). Similar for
> sch_dsmark.
>
> Instead of fixing each separately, Linus suggested to just accept
> NULL pointer in qdisc_put(), which would make callers easier.
>
> (For sch_dsmark, the bug probably exists long before commit
> 6529eaba33f0.)
>
> Fixes: 6529eaba33f0 ("net: sched: introduce tcf block infractructure")
> Reported-by: syzbot+d5870a903591faaca...@syzkaller.appspotmail.com
> Suggested-by: Linus Torvalds <torva...@linux-foundation.org>
> Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
Applied and queued up for -stable, thanks.
