5.15-stable review patch. If anyone has any objections, please let me know.
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From: Cong Wang xiyou.wangcong@gmail.com
[ Upstream commit 2d3cbfd6d54a2c39ce3244f33f85c595844bd7b8 ]
Previously, when reducing a qdisc's limit via the ->change() operation, only the main skb queue was trimmed, potentially leaving packets in the gso_skb list. This could result in NULL pointer dereference when we only check sch->limit against sch->q.qlen.
This patch introduces a new helper, qdisc_dequeue_internal(), which ensures both the gso_skb list and the main queue are properly flushed when trimming excess packets. All relevant qdiscs (codel, fq, fq_codel, fq_pie, hhf, pie) are updated to use this helper in their ->change() routines.
Fixes: 76e3cc126bb2 ("codel: Controlled Delay AQM") Fixes: 4b549a2ef4be ("fq_codel: Fair Queue Codel AQM") Fixes: afe4fd062416 ("pkt_sched: fq: Fair Queue packet scheduler") Fixes: ec97ecf1ebe4 ("net: sched: add Flow Queue PIE packet scheduler") Fixes: 10239edf86f1 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc") Fixes: d4b36210c2e6 ("net: pkt_sched: PIE AQM scheme") Reported-by: Will willsroot@protonmail.com Reported-by: Savy savy@syst3mfailure.io Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/sch_generic.h | 15 +++++++++++++++ net/sched/sch_codel.c | 2 +- net/sched/sch_fq.c | 2 +- net/sched/sch_fq_codel.c | 2 +- net/sched/sch_fq_pie.c | 2 +- net/sched/sch_hhf.c | 2 +- net/sched/sch_pie.c | 2 +- 7 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index 0919dfd3a67a6..55127305478df 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -1035,6 +1035,21 @@ static inline struct sk_buff *__qdisc_dequeue_head(struct qdisc_skb_head *qh) return skb; }
+static inline struct sk_buff *qdisc_dequeue_internal(struct Qdisc *sch, bool direct) +{ + struct sk_buff *skb; + + skb = __skb_dequeue(&sch->gso_skb); + if (skb) { + sch->q.qlen--; + return skb; + } + if (direct) + return __qdisc_dequeue_head(&sch->q); + else + return sch->dequeue(sch); +} + static inline struct sk_buff *qdisc_dequeue_head(struct Qdisc *sch) { struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c index 30169b3adbbb0..d99c7386e24e6 100644 --- a/net/sched/sch_codel.c +++ b/net/sched/sch_codel.c @@ -174,7 +174,7 @@ static int codel_change(struct Qdisc *sch, struct nlattr *opt,
qlen = sch->q.qlen; while (sch->q.qlen > sch->limit) { - struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); + struct sk_buff *skb = qdisc_dequeue_internal(sch, true);
dropped += qdisc_pkt_len(skb); qdisc_qstats_backlog_dec(sch, skb); diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c index 5a1274199fe33..65b12b39e2ec5 100644 --- a/net/sched/sch_fq.c +++ b/net/sched/sch_fq.c @@ -904,7 +904,7 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt, sch_tree_lock(sch); } while (sch->q.qlen > sch->limit) { - struct sk_buff *skb = fq_dequeue(sch); + struct sk_buff *skb = qdisc_dequeue_internal(sch, false);
if (!skb) break; diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c index efda894bbb78b..f954969ea8fec 100644 --- a/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c @@ -429,7 +429,7 @@ static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt,
while (sch->q.qlen > sch->limit || q->memory_usage > q->memory_limit) { - struct sk_buff *skb = fq_codel_dequeue(sch); + struct sk_buff *skb = qdisc_dequeue_internal(sch, false);
q->cstats.drop_len += qdisc_pkt_len(skb); rtnl_kfree_skbs(skb, skb); diff --git a/net/sched/sch_fq_pie.c b/net/sched/sch_fq_pie.c index 1fb68c973f451..30259c8756451 100644 --- a/net/sched/sch_fq_pie.c +++ b/net/sched/sch_fq_pie.c @@ -360,7 +360,7 @@ static int fq_pie_change(struct Qdisc *sch, struct nlattr *opt,
/* Drop excess packets if new limit is lower */ while (sch->q.qlen > sch->limit) { - struct sk_buff *skb = fq_pie_qdisc_dequeue(sch); + struct sk_buff *skb = qdisc_dequeue_internal(sch, false);
len_dropped += qdisc_pkt_len(skb); num_dropped += 1; diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c index 420ede8753229..433bddcbc0c72 100644 --- a/net/sched/sch_hhf.c +++ b/net/sched/sch_hhf.c @@ -563,7 +563,7 @@ static int hhf_change(struct Qdisc *sch, struct nlattr *opt, qlen = sch->q.qlen; prev_backlog = sch->qstats.backlog; while (sch->q.qlen > sch->limit) { - struct sk_buff *skb = hhf_dequeue(sch); + struct sk_buff *skb = qdisc_dequeue_internal(sch, false);
rtnl_kfree_skbs(skb, skb); } diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c index 5a457ff61acd8..67ce65af52b5c 100644 --- a/net/sched/sch_pie.c +++ b/net/sched/sch_pie.c @@ -193,7 +193,7 @@ static int pie_change(struct Qdisc *sch, struct nlattr *opt, /* Drop excess packets if new limit is lower */ qlen = sch->q.qlen; while (sch->q.qlen > sch->limit) { - struct sk_buff *skb = __qdisc_dequeue_head(&sch->q); + struct sk_buff *skb = qdisc_dequeue_internal(sch, true);
dropped += qdisc_pkt_len(skb); qdisc_qstats_backlog_dec(sch, skb);