[PATCH net-next 08/15] net/sched: sch_fq_codel: remove data-races from fq_codel_dump_stats()

[Eric Dumazet <edumazet@google.com>]

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

Move this acquisition before we fill st.qdisc_stats with live data.

Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump")
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 net/sched/sch_fq_codel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index 5c88278a30b3cd92ae525d1a88eb692ff0e296e0..db5cf578cbd63e842381cb147ced145fed4cca3e 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -586,6 +586,8 @@ static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 	};
 	struct list_head *pos;
 
+	sch_tree_lock(sch);
+
 	st.qdisc_stats.maxpacket = q->cstats.maxpacket;
 	st.qdisc_stats.drop_overlimit = q->drop_overlimit;
 	st.qdisc_stats.ecn_mark = q->cstats.ecn_mark;
@@ -594,7 +596,6 @@ static int fq_codel_dump_stats(struct Qdisc *sch, struct gnet_dump *d)
 	st.qdisc_stats.memory_usage  = q->memory_usage;
 	st.qdisc_stats.drop_overmemory = q->drop_overmemory;
 
-	sch_tree_lock(sch);
 	list_for_each(pos, &q->new_flows)
 		st.qdisc_stats.new_flows_len++;
 
-- 
2.53.0.1213.gd9a14994de-goog