From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Fri, 3 Apr 2020 03:58:51 +0000 (-0700)
Subject: net_sched: fix a missing refcnt in tcindex_init()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=a8eab6d35e22f4f21471f16147be79529cd6aaf7;p=linux.git

net_sched: fix a missing refcnt in tcindex_init()

The initial refcnt of struct tcindex_data should be 1,
it is clear that I forgot to set it to 1 in tcindex_init().
This leads to a dec-after-zero warning.

Reported-by: syzbot+8325e509a1bf83ec741d@syzkaller.appspotmail.com
Fixes: 304e024216a8 ("net_sched: add a temporary refcnt for struct tcindex_data")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 065345832a697..61e95029c18f5 100644
--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -151,6 +151,7 @@ static int tcindex_init(struct tcf_proto *tp)
 	p->mask = 0xffff;
 	p->hash = DEFAULT_HASH_SIZE;
 	p->fall_through = 1;
+	refcount_set(&p->refcnt, 1); /* Paired with tcindex_destroy_work() */
 
 	rcu_assign_pointer(tp->root, p);
 	return 0;