netdev - [Patch net] net_sched: fix a missing refcnt in tcindex

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Date:   Thu,  2 Apr 2020 20:58:51 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     netdev@...r.kernel.org
Cc:     Cong Wang <xiyou.wangcong@...il.com>,
        syzbot+8325e509a1bf83ec741d@...kaller.appspotmail.com,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: [Patch net] 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@...kaller.appspotmail.com
Fixes: 304e024216a8 ("net_sched: add a temporary refcnt for struct tcindex_data")
Cc: Jamal Hadi Salim <jhs@...atatu.com>
Cc: Jiri Pirko <jiri@...nulli.us>
Cc: Paul E. McKenney <paulmck@...nel.org>
Signed-off-by: Cong Wang <xiyou.wangcong@...il.com>
---
 net/sched/cls_tcindex.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/sched/cls_tcindex.c b/net/sched/cls_tcindex.c
index 065345832a69..61e95029c18f 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;
-- 
2.21.1