Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
net/sched: sch_fq_codel: annotate data-races from fq_codel_dump_class_stats()
fq_codel_dump_class_stats() acquires qdisc spinlock only when requested
to follow flow->head chain.
As we did in sch_cake recently, add the missing READ_ONCE()/WRITE_ONCE()
annotations.
Fixes: edb09eb17ed8 ("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/20260504163842.1162001-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
authored by
Eric Dumazet
and committed by
Jakub Kicinski
f83e07b2
40aa9fce
+20
-19
+20
-19
net/sched/sch_fq_codel.c
+20
-19
net/sched/sch_fq_codel.c
···
117
117
{
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struct sk_buff *skb = flow->head;
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-
flow->head = skb->next;
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+
WRITE_ONCE(flow->head, skb->next);
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skb_mark_not_on_list(skb);
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return skb;
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}
···
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struct sk_buff *skb)
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{
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if (flow->head == NULL)
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-
flow->head = skb;
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+
WRITE_ONCE(flow->head, skb);
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else
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flow->tail->next = skb;
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flow->tail = skb;
···
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} while (++i < max_packets && len < threshold);
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/* Tell codel to increase its signal strength also */
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-
flow->cvars.count += i;
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-
q->backlogs[idx] -= len;
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+
WRITE_ONCE(flow->cvars.count, flow->cvars.count + i);
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+
WRITE_ONCE(q->backlogs[idx], q->backlogs[idx] - len);
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q->memory_usage -= mem;
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sch->qstats.drops += i;
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sch->qstats.backlog -= len;
···
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codel_set_enqueue_time(skb);
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flow = &q->flows[idx];
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flow_queue_add(flow, skb);
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-
q->backlogs[idx] += qdisc_pkt_len(skb);
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+
WRITE_ONCE(q->backlogs[idx], q->backlogs[idx] + qdisc_pkt_len(skb));
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qdisc_qstats_backlog_inc(sch, skb);
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if (list_empty(&flow->flowchain)) {
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list_add_tail(&flow->flowchain, &q->new_flows);
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q->new_flow_count++;
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-
flow->deficit = q->quantum;
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+
WRITE_ONCE(flow->deficit, q->quantum);
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}
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get_codel_cb(skb)->mem_usage = skb->truesize;
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q->memory_usage += get_codel_cb(skb)->mem_usage;
···
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flow = container_of(vars, struct fq_codel_flow, cvars);
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if (flow->head) {
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skb = dequeue_head(flow);
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-
q->backlogs[flow - q->flows] -= qdisc_pkt_len(skb);
266
+
WRITE_ONCE(q->backlogs[flow - q->flows],
267
+
q->backlogs[flow - q->flows] - qdisc_pkt_len(skb));
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q->memory_usage -= get_codel_cb(skb)->mem_usage;
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sch->q.qlen--;
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sch->qstats.backlog -= qdisc_pkt_len(skb);
···
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flow = list_first_entry(head, struct fq_codel_flow, flowchain);
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if (flow->deficit <= 0) {
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-
flow->deficit += q->quantum;
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+
WRITE_ONCE(flow->deficit, flow->deficit + q->quantum);
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list_move_tail(&flow->flowchain, &q->old_flows);
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goto begin;
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}
···
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goto begin;
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}
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qdisc_bstats_update(sch, skb);
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-
flow->deficit -= qdisc_pkt_len(skb);
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+
WRITE_ONCE(flow->deficit, flow->deficit - qdisc_pkt_len(skb));
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if (q->cstats.drop_count) {
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qdisc_tree_reduce_backlog(sch, q->cstats.drop_count,
···
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static void fq_codel_flow_purge(struct fq_codel_flow *flow)
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{
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rtnl_kfree_skbs(flow->head, flow->tail);
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-
flow->head = NULL;
331
+
WRITE_ONCE(flow->head, NULL);
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}
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static void fq_codel_reset(struct Qdisc *sch)
···
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memset(&xstats, 0, sizeof(xstats));
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xstats.type = TCA_FQ_CODEL_XSTATS_CLASS;
660
-
xstats.class_stats.deficit = flow->deficit;
659
+
xstats.class_stats.deficit = READ_ONCE(flow->deficit);
661
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xstats.class_stats.ldelay =
662
-
codel_time_to_us(flow->cvars.ldelay);
663
-
xstats.class_stats.count = flow->cvars.count;
664
-
xstats.class_stats.lastcount = flow->cvars.lastcount;
665
-
xstats.class_stats.dropping = flow->cvars.dropping;
666
-
if (flow->cvars.dropping) {
667
-
codel_tdiff_t delta = flow->cvars.drop_next -
661
+
codel_time_to_us(READ_ONCE(flow->cvars.ldelay));
662
+
xstats.class_stats.count = READ_ONCE(flow->cvars.count);
663
+
xstats.class_stats.lastcount = READ_ONCE(flow->cvars.lastcount);
664
+
xstats.class_stats.dropping = READ_ONCE(flow->cvars.dropping);
665
+
if (xstats.class_stats.dropping) {
666
+
codel_tdiff_t delta = READ_ONCE(flow->cvars.drop_next) -
668
667
codel_get_time();
669
668
670
669
xstats.class_stats.drop_next = (delta >= 0) ?
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codel_time_to_us(delta) :
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-codel_time_to_us(-delta);
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672
}
674
-
if (flow->head) {
673
+
if (READ_ONCE(flow->head)) {
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sch_tree_lock(sch);
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skb = flow->head;
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while (skb) {
···
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}
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sch_tree_unlock(sch);
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681
}
683
-
qs.backlog = q->backlogs[idx];
682
+
qs.backlog = READ_ONCE(q->backlogs[idx]);
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qs.drops = 0;
685
684
}
686
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if (gnet_stats_copy_queue(d, NULL, &qs, qs.qlen) < 0)