net: sched: fix ordering of qlen adjustment
commit 5eb7de8cd58e73851cd37ff8d0666517d9926948 upstream.
Changes to sch->q.qlen around qdisc_tree_reduce_backlog() need to happen
_before_ a call to said function because otherwise it may fail to notify
parent qdiscs when the child is about to become empty.
BUG=b/385096878
TEST=presubmit
RELEASE_NOTE=Fixed KCTF-5eb7de8 in the Linux kernel.
cos-patch: security-high
Change-Id: Id628c7ca647b43a5f5b1e004aef434a64001e2b8
Signed-off-by: Lion Ackermann <nnamrec@gmail.com>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Artem Metla <ametla@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kernel CVE Triage Automation <cloud-image-kernel-cve-triage-automation@prod.google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/89379
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
Reviewed-by: Shuo Yang <gshuoy@google.com>
Reviewed-by: He Gao <hegao@google.com>
diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c
index 30955dd..a65fad4 100644
--- a/net/sched/sch_cake.c
+++ b/net/sched/sch_cake.c
@@ -1542,7 +1542,6 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
b->backlogs[idx] -= len;
b->tin_backlog -= len;
sch->qstats.backlog -= len;
- qdisc_tree_reduce_backlog(sch, 1, len);
flow->dropped++;
b->tin_dropped++;
@@ -1553,6 +1552,7 @@ static unsigned int cake_drop(struct Qdisc *sch, struct sk_buff **to_free)
__qdisc_drop(skb, to_free);
sch->q.qlen--;
+ qdisc_tree_reduce_backlog(sch, 1, len);
cake_heapify(q, 0);
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index 19c8511..a919591 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -123,10 +123,10 @@ static void choke_drop_by_idx(struct Qdisc *sch, unsigned int idx,
if (idx == q->tail)
choke_zap_tail_holes(q);
+ --sch->q.qlen;
qdisc_qstats_backlog_dec(sch, skb);
qdisc_tree_reduce_backlog(sch, 1, qdisc_pkt_len(skb));
qdisc_drop(skb, sch, to_free);
- --sch->q.qlen;
}
struct choke_skb_cb {
