From 700b4c6c70d6a36e6878c5ea092c4877da3f10d8 Mon Sep 17 00:00:00 2001 From: Jamal Hadi Salim Date: Tue, 20 Oct 2026 07:00:08 -0400 Subject: [PATCH] net/sched/sch_cake: drop dead nla_nest_end() error check MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit cake_dump_class_stats() closes the TCA_STATS_APP nest with if (nla_nest_end(d->skb, stats) < 0) return -1; nla_nest_end() never returns a negative value: it has a single `return skb->len;` and no error path (that is why the overflow-aware nla_nest_end_safe() helper was later added). The '< 0' test can never be true, so the 'return -1' is unreachable dead code. Drop the check and close the nest with the bare statement, matching the sibling cake nests in the same file. This issue was discovered while fixing a bug on the gate action, see: https://lore.kernel.org/netdev/QDISC-H19Z.v1.20261001053234@mojatatu.com/ Conditions to recreate the bug: - not runtime observable: the issue is found by inspection. Link: https://lore.kernel.org/netdev/87v77csd5q.fsf@toke.dk/ Reviewed-by: Victor Nogueira Acked-by: Toke Høiland-Jørgensen Signed-off-by: Jamal Hadi Salim Link: https://patch.msgid.link/QDISC-5RTM.v3.r0.20261020053711-4@mojatatu.com Signed-off-by: Jakub Kicinski --- net/sched/sch_cake.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/net/sched/sch_cake.c b/net/sched/sch_cake.c index e74f85fc373f..aa4043d662c1 100644 --- a/net/sched/sch_cake.c +++ b/net/sched/sch_cake.c @@ -3226,8 +3226,7 @@ static int cake_dump_class_stats(struct Qdisc *sch, unsigned long cl, READ_ONCE(flow->cvars.drop_next)))); } - if (nla_nest_end(d->skb, stats) < 0) - return -1; + nla_nest_end(d->skb, stats); } return 0;