net_sched: sch_fq: clear q->band_pkt_count[] in fq_reset()

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>

diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index 80235e85f8440ee83032f171cf28df6f161473db..05084c9af48e1c7254a695b30293806a8ac78632 100644 (file)
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -827,6 +827,7 @@ 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;