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net_sched: sch_hhf: annotate data-races in hhf_dump_stats()

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hhf_dump_stats() only runs with RTNL held,
reading fields that can be changed in qdisc fast path.

Add READ_ONCE()/WRITE_ONCE() annotations.

Fixes: edb09eb17e ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20260421143349.4052215-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2026-04-21 14:33:49 +00:00 committed by Jakub Kicinski
parent 9d146a5d10
commit a6edf2cd41
1 changed files with 10 additions and 9 deletions
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19
net/sched/sch_hhf.c
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@ -198,7 +198,8 @@ static struct hh_flow_state *seek_list(const u32 hash,
return NULL;
list_del(&flow->flowchain);
kfree(flow);
q->hh_flows_current_cnt--;
WRITE_ONCE(q->hh_flows_current_cnt,
q->hh_flows_current_cnt - 1);
} else if (flow->hash_id == hash) {
return flow;
}
@ -226,7 +227,7 @@ static struct hh_flow_state *alloc_new_hh(struct list_head *head,
}
if (q->hh_flows_current_cnt >= q->hh_flows_limit) {
q->hh_flows_overlimit++;
WRITE_ONCE(q->hh_flows_overlimit, q->hh_flows_overlimit + 1);
return NULL;
}
/* Create new entry. */
@ -234,7 +235,7 @@ static struct hh_flow_state *alloc_new_hh(struct list_head *head,
if (!flow)
return NULL;
q->hh_flows_current_cnt++;
WRITE_ONCE(q->hh_flows_current_cnt, q->hh_flows_current_cnt + 1);
INIT_LIST_HEAD(&flow->flowchain);
list_add_tail(&flow->flowchain, head);
@ -309,7 +310,7 @@ static enum wdrr_bucket_idx hhf_classify(struct sk_buff *skb, struct Qdisc *sch)
return WDRR_BUCKET_FOR_NON_HH;
flow->hash_id = hash;
flow->hit_timestamp = now;
q->hh_flows_total_cnt++;
WRITE_ONCE(q->hh_flows_total_cnt, q->hh_flows_total_cnt + 1);
/* By returning without updating counters in q->hhf_arrays,
* we implicitly implement "shielding" (see Optimization O1).
@ -403,7 +404,7 @@ static int hhf_enqueue(struct sk_buff *skb, struct Qdisc *sch,
return NET_XMIT_SUCCESS;
prev_backlog = sch->qstats.backlog;
q->drop_overlimit++;
WRITE_ONCE(q->drop_overlimit, q->drop_overlimit + 1);
/* Return Congestion Notification only if we dropped a packet from this
* bucket.
*/
@ -686,10 +687,10 @@ static int hhf_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
{
struct hhf_sched_data *q = qdisc_priv(sch);
struct tc_hhf_xstats st = {
.drop_overlimit = q->drop_overlimit,
.hh_overlimit = q->hh_flows_overlimit,
.hh_tot_count = q->hh_flows_total_cnt,
.hh_cur_count = q->hh_flows_current_cnt,
.drop_overlimit = READ_ONCE(q->drop_overlimit),
.hh_overlimit = READ_ONCE(q->hh_flows_overlimit),
.hh_tot_count = READ_ONCE(q->hh_flows_total_cnt),
.hh_cur_count = READ_ONCE(q->hh_flows_current_cnt),
};
return gnet_stats_copy_app(d, &st, sizeof(st));