From efb55222d31c8c2af8b4ba42bb56b0b0beedf98e Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Fri, 30 Aug 2019 04:07:21 +0300 Subject: [PATCH] taprio: Fix kernel panic in taprio_destroy taprio_init may fail earlier than this line: list_add(&q->taprio_list, &taprio_list); i.e. due to the net device not being multi queue. Attempting to remove q from the global taprio_list when it is not part of it will result in a kernel panic. Fix it by matching list_add and list_del better to one another in the order of operations. This way we can keep the deletion unconditional and with lower complexity - O(1). Cc: Leandro Dorileo Fixes: 7b9eba7ba0c1 ("net/sched: taprio: fix picos_per_byte miscalculation") Signed-off-by: Vladimir Oltean Acked-by: Vinicius Costa Gomes Signed-off-by: David S. Miller --- net/sched/sch_taprio.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index e25d414ae12f..8c85f61e98dd 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1249,6 +1249,10 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt, */ q->clockid = -1; + spin_lock(&taprio_list_lock); + list_add(&q->taprio_list, &taprio_list); + spin_unlock(&taprio_list_lock); + if (sch->parent != TC_H_ROOT) return -EOPNOTSUPP; @@ -1266,10 +1270,6 @@ static int taprio_init(struct Qdisc *sch, struct nlattr *opt, if (!opt) return -EINVAL; - spin_lock(&taprio_list_lock); - list_add(&q->taprio_list, &taprio_list); - spin_unlock(&taprio_list_lock); - for (i = 0; i < dev->num_tx_queues; i++) { struct netdev_queue *dev_queue; struct Qdisc *qdisc; -- 2.11.0