Commit 59b14577 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net/sched: sch_fq_pie: annotate data-races in fq_pie_dump_stats() 



fq_codel_dump_stats() acquires the qdisc spinlock a bit too late.

Move this acquisition before we fill tc_fq_pie_xstats with live data.

Alternative would be to add READ_ONCE() and WRITE_ONCE() annotations,
but the spinlock is needed anyway to scan q->new_flows and q->old_flows.

Fixes: ec97ecf1 ("net: sched: add Flow Queue PIE packet scheduler")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20260423063527.2568262-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent d3aeb889

net/sched/sch_fq_pie.c

+10 −9
Original line number Diff line number Diff line
@@ -509,18 +509,19 @@ static int fq_pie_dump(struct Qdisc *sch, struct sk_buff *skb) 
static int fq_pie_dump_stats(struct Qdisc *sch, struct gnet_dump *d)

{

	struct fq_pie_sched_data *q = qdisc_priv(sch);

	struct tc_fq_pie_xstats st = {

		.packets_in	= q->stats.packets_in,

		.overlimit	= q->stats.overlimit,

		.overmemory	= q->overmemory,

		.dropped	= q->stats.dropped,

		.ecn_mark	= q->stats.ecn_mark,

		.new_flow_count = q->new_flow_count,

		.memory_usage   = q->memory_usage,

	};

	struct tc_fq_pie_xstats st = { 0 };

	struct list_head *pos;



	sch_tree_lock(sch);



	st.packets_in	= q->stats.packets_in;

	st.overlimit	= q->stats.overlimit;

	st.overmemory	= q->overmemory;

	st.dropped	= q->stats.dropped;

	st.ecn_mark	= q->stats.ecn_mark;

	st.new_flow_count = q->new_flow_count;

	st.memory_usage   = q->memory_usage;



	list_for_each(pos, &q->new_flows)

		st.new_flows_len++;