[PATCH 6.18 282/314] net_sched: sch_fq: clear q->band_pkt_count[] in fq_reset()

Sasha Levin
2026-03-10T11:29:53Z

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit a4c2b8be2e5329e7fac6e8f64ddcb8958155cfcb ]

When/if a NIC resets, queues are deactivated by dev_deactivate_many(),
then reactivated when the reset operation completes.

fq_reset() removes all the skbs from various queues.

If we do not clear q->band_pkt_count[], these counters keep growing
and can eventually reach sch->limit, preventing new packets to be queued.

Many thanks to Praveen for discovering the root cause.

Fixes: 29f834aa326e ("net_sched: sch_fq: add 3 bands and WRR scheduling")
Diagnosed-by: Praveen Kaligineedi <pkaligineedi@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20260304015640.961780-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/sched/sch_fq.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index fee922da2f99c..5e41930079948 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -826,6 +826,7 @@ static void fq_reset(struct Qdisc *sch)
for (idx = 0; idx < FQ_BANDS; idx++) {
q->band_flows[idx].new_flows.first = NULL;
q->band_flows[idx].old_flows.first = NULL;
+ q->band_pkt_count[idx] = 0;
}
q->delayed = RB_ROOT;
q->flows = 0;
--
2.51.0