From c71c512f4a65267e6a18163f4df729c489a51035 Mon Sep 17 00:00:00 2001 From: Davide Caratti Date: Wed, 16 Dec 2020 19:33:29 +0100 Subject: [PATCH] net/sched: sch_taprio: reset child qdiscs before freeing them [ Upstream commit 44d4775ca51805b376a8db5b34f650434a08e556 ] 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 Acked-by: Vinicius Costa Gomes Link: https://lore.kernel.org/r/63b6d79b0e830ebb0283e020db4df3cdfdfb2b94.1608142843.git.dcaratti@redhat.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- 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 2b797a71e9bd..f2b1305e79d2 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1597,6 +1597,21 @@ free_sched: 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,