From: Davide Caratti <dcaratti@xxxxxxxxxx> [ Upstream commit 698285da79f5b0b099db15a37ac661ac408c80eb ] taprio_graft() can insert a NULL element in the array of child qdiscs. As a consquence, taprio_reset() might not reset child qdiscs completely, and taprio_destroy() might leak resources. Fix it by ensuring that loops that iterate over q->qdiscs[] don't end when they find the first NULL item. Fixes: 44d4775ca518 ("net/sched: sch_taprio: reset child qdiscs before freeing them") Fixes: 5a781ccbd19e ("tc: Add support for configuring the taprio scheduler") Suggested-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Davide Caratti <dcaratti@xxxxxxxxxx> Link: https://lore.kernel.org/r/13edef6778fef03adc751582562fba4a13e06d6a.1608240532.git.dcaratti@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/sch_taprio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1626,7 +1626,7 @@ static void taprio_destroy(struct Qdisc taprio_disable_offload(dev, q, NULL); if (q->qdiscs) { - for (i = 0; i < dev->num_tx_queues && q->qdiscs[i]; i++) + for (i = 0; i < dev->num_tx_queues; i++) qdisc_put(q->qdiscs[i]); kfree(q->qdiscs);