net_sched: initialize timer earlier in red_init()

When red_init() fails, red_destroy() is called to clean up.
If the timer is not initialized yet, del_timer_sync() will
complain. So we have to move timer_setup() before any failure.

Reported-and-tested-by: syzbot+6e95a4fabf88dc217145@syzkaller.appspotmail.com
Fixes: aee9caa ("net: sched: sch_red: Add qevents "early_drop" and "mark"")
Cc: Petr Machata <petrm@mellanox.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Petr Machata <petrm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/sch_red.c

@@ -333,6 +333,10 @@ static int red_init(struct Qdisc *sch, struct nlattr *opt,
 	struct nlattr *tb[TCA_RED_MAX + 1];
 	int err;
 
+	q->qdisc = &noop_qdisc;
+	q->sch = sch;
+	timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
+
 	if (!opt)
 		return -EINVAL;
 
@@ -341,10 +345,6 @@ static int red_init(struct Qdisc *sch, struct nlattr *opt,
 	if (err < 0)
 		return err;
 
-	q->qdisc = &noop_qdisc;
-	q->sch = sch;
-	timer_setup(&q->adapt_timer, red_adaptative_timer, 0);
-
 	err = __red_change(sch, tb, extack);
 	if (err)
 		return err;