[Patch net-next] net_sched: initialize timer earlier in red_init()

[Cong Wang]

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+6e95a4fabf88dc217...@syzkaller.appspotmail.com
Fixes: aee9caa03fc3 ("net: sched: sch_red: Add qevents "early_drop" and "mark"")
Cc: Petr Machata <pe...@mellanox.com>
Cc: Jamal Hadi Salim <j...@mojatatu.com>
Cc: Jiri Pirko <j...@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
 net/sched/sch_red.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c
index 4cc0ad0b1189..deac82f3ad7b 100644
--- a/net/sched/sch_red.c
+++ b/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;
-- 
2.27.0