[PATCH net] net/sched: sch_taprio: reset child qdiscs before freeing them
From: Davide Caratti <hidden>
Date: 2020-12-16 18:35:39
Subsystem:
cbs/etf/taprio qdiscs, networking [general], tc subsystem, the rest · Maintainers:
Vinicius Costa Gomes, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Jamal Hadi Salim, Jiri Pirko, Linus Torvalds
syzkaller shows that packets can still be dequeued while taprio_destroy()
is running. Let sch_taprio use the reset() function to cancel the advance
timer and drop all skbs from the child qdiscs.
Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler")
Link: https://syzkaller.appspot.com/bug?id=f362872379bf8f0017fb667c1ab158f2d1e764ae
Reported-by: syzbot+8971da381fb5a31f542d@syzkaller.appspotmail.com
Signed-off-by: Davide Caratti <redacted>
---
net/sched/sch_taprio.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c
index 26fb8a62996b..c74817ec9964 100644
--- a/net/sched/sch_taprio.c
+++ b/net/sched/sch_taprio.c@@ -1597,6 +1597,21 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, return err; } +static void taprio_reset(struct Qdisc *sch) +{ + struct taprio_sched *q = qdisc_priv(sch); + struct net_device *dev = qdisc_dev(sch); + int i; + + hrtimer_cancel(&q->advance_timer); + if (q->qdiscs) { + for (i = 0; i < dev->num_tx_queues && q->qdiscs[i]; i++) + qdisc_reset(q->qdiscs[i]); + } + sch->qstats.backlog = 0; + sch->q.qlen = 0; +} + static void taprio_destroy(struct Qdisc *sch) { struct taprio_sched *q = qdisc_priv(sch);
@@ -1607,7 +1622,6 @@ static void taprio_destroy(struct Qdisc *sch) list_del(&q->taprio_list); spin_unlock(&taprio_list_lock); - hrtimer_cancel(&q->advance_timer); taprio_disable_offload(dev, q, NULL);
@@ -1954,6 +1968,7 @@ static struct Qdisc_ops taprio_qdisc_ops __read_mostly = { .init = taprio_init, .change = taprio_change, .destroy = taprio_destroy, + .reset = taprio_reset, .peek = taprio_peek, .dequeue = taprio_dequeue, .enqueue = taprio_enqueue,
--
2.29.2