diff mbox series

[net,1/2] sch_htb: Fix select_queue for non-offload mode

Message ID 20210311144206.2135872-2-maximmi@nvidia.com
State New
Headers show
Series Bugfixes for HTB | expand

Commit Message

Maxim Mikityanskiy March 11, 2021, 2:42 p.m. UTC 
htb_select_queue assumes it's always the offload mode, and it ends up in
calling ndo_setup_tc without any checks. It may lead to a NULL pointer
dereference if ndo_setup_tc is not implemented, or to an error returned
from the driver, which will prevent attaching qdiscs to HTB classes in
the non-offload mode.

This commit fixes the bug by adding the missing check to
htb_select_queue. In the non-offload mode it will return sch->dev_queue,
mimicking tc_modify_qdisc's behavior for the case where select_queue is
not implemented.

Reported-by: syzbot+b53a709f04722ca12a3c@syzkaller.appspotmail.com
Fixes: d03b195b5aa0 ("sch_htb: Hierarchical QoS hardware offload")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
---
 net/sched/sch_htb.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index dff3adf5a915..b23203159996 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -1340,8 +1340,12 @@  htb_select_queue(struct Qdisc *sch, struct tcmsg *tcm)
 {
 	struct net_device *dev = qdisc_dev(sch);
 	struct tc_htb_qopt_offload offload_opt;
+	struct htb_sched *q = qdisc_priv(sch);
 	int err;
 
+	if (!q->offload)
+		return sch->dev_queue;
+
 	offload_opt = (struct tc_htb_qopt_offload) {
 		.command = TC_HTB_LEAF_QUERY_QUEUE,
 		.classid = TC_H_MIN(tcm->tcm_parent),