From: Davide Caratti dcaratti@redhat.com
[ 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=f362872379bf8f0017fb667c1ab158f2d1e764a... Reported-by: syzbot+8971da381fb5a31f542d@syzkaller.appspotmail.com Signed-off-by: Davide Caratti dcaratti@redhat.com Acked-by: Vinicius Costa Gomes vinicius.gomes@intel.com Link: https://lore.kernel.org/r/63b6d79b0e830ebb0283e020db4df3cdfdfb2b94.160814284... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/sch_taprio.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
--- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1596,6 +1596,21 @@ 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); @@ -1606,7 +1621,6 @@ static void taprio_destroy(struct Qdisc list_del(&q->taprio_list); spin_unlock(&taprio_list_lock);
- hrtimer_cancel(&q->advance_timer);
taprio_disable_offload(dev, q, NULL);
@@ -1953,6 +1967,7 @@ static struct Qdisc_ops taprio_qdisc_ops .init = taprio_init, .change = taprio_change, .destroy = taprio_destroy, + .reset = taprio_reset, .peek = taprio_peek, .dequeue = taprio_dequeue, .enqueue = taprio_enqueue,