path: root/net/sched/sch_hfsc.c
diff options
authorToke Høiland-Jørgensen <toke@redhat.com>2019-01-09 17:09:43 +0100
committerDavid S. Miller <davem@davemloft.net>2019-01-15 20:12:00 -0800
commit37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea (patch)
tree29e8d6fccf9da0a9c19129f477a0ef0ae244464d /net/sched/sch_hfsc.c
parentsched: Avoid dereferencing skb pointer after child enqueue (diff)
sched: Fix detection of empty queues in child qdiscs
Several qdiscs check on enqueue whether the packet was enqueued to a class with an empty queue, in which case the class is activated. This is done by checking if the qlen is exactly 1 after enqueue. However, if GSO splitting is enabled in the child qdisc, a single packet can result in a qlen longer than 1. This means the activation check fails, leading to a stalled queue. Fix this by checking if the queue is empty *before* enqueue, and running the activation logic if this was the case. Reported-by: Pete Heist <pete@heistp.net> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_hfsc.c')
1 files changed, 3 insertions, 1 deletions
diff --git a/net/sched/sch_hfsc.c b/net/sched/sch_hfsc.c
index 6bb8f73a8473..24cc220a3218 100644
--- a/net/sched/sch_hfsc.c
+++ b/net/sched/sch_hfsc.c
@@ -1542,6 +1542,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
unsigned int len = qdisc_pkt_len(skb);
struct hfsc_class *cl;
int uninitialized_var(err);
+ bool first;
cl = hfsc_classify(skb, sch, &err);
if (cl == NULL) {
@@ -1551,6 +1552,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
return err;
+ first = !cl->qdisc->q.qlen;
err = qdisc_enqueue(skb, cl->qdisc, to_free);
if (unlikely(err != NET_XMIT_SUCCESS)) {
if (net_xmit_drop_count(err)) {
@@ -1560,7 +1562,7 @@ hfsc_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free)
return err;
- if (cl->qdisc->q.qlen == 1) {
+ if (first) {
if (cl->cl_flags & HFSC_RSC)
init_ed(cl, len);
if (cl->cl_flags & HFSC_FSC)