From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu, 2 Apr 2020 20:58:51 -0700
Subject: net_sched: fix a missing refcnt in tcindex_init()
Git-commit: a8eab6d35e22f4f21471f16147be79529cd6aaf7
Patch-mainline: 5.7-rc1
References: networking-stable-20_04_09

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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 net/sched/cls_tcindex.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/sched/cls_tcindex.c
+++ b/net/sched/cls_tcindex.c
@@ -151,6 +151,7 @@ static int tcindex_init(struct tcf_proto
 	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;