net_sched: fix a crash in tc_new_tfilter()
authorCong Wang <xiyou.wangcong@gmail.com>
Thu, 27 Sep 2018 20:42:19 +0000 (13:42 -0700)
committerDavid S. Miller <davem@davemloft.net>
Tue, 2 Oct 2018 06:09:41 +0000 (23:09 -0700)
commit460b360104d51552a57f39e54b2589c9fd7fa0b3
tree84082e01896498cde177e058e72e6509786055bf
parenta1fa80802cb02cb043fd61b87bc81c06a38b4bb1
net_sched: fix a crash in tc_new_tfilter()

When tcf_block_find() fails, it already rollbacks the qdisc refcnt,
so its caller doesn't need to clean up this again. Avoid calling
qdisc_put() again by resetting qdisc to NULL for callers.

Reported-by: syzbot+37b8770e6d5a8220a039@syzkaller.appspotmail.com
Fixes: e368fdb61d8e ("net: sched: use Qdisc rcu API instead of relying on rtnl lock")
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/sched/cls_api.c