From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
Jamal Hadi Salim <jhs@mojatatu.com>,
Jiri Pirko <jiri@resnulli.us>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>
Subject: [PATCH net] net/sched: sch_fq_codel: remove data-races from fq_codel_dump_stats()
Date: Tue, 21 Apr 2026 14:25:09 +0000 [thread overview]
Message-ID: <20260421142509.3967231-1-edumazet@google.com> (raw)
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>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.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 2a3d758f67ab43d17128442fd8b51c6ba7775d52..0664b2f2d6f28041e5250a44fc92311116ae0cf1 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -585,6 +585,8 @@ 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;
@@ -593,7 +595,6 @@ 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++;
--
2.54.0.rc2.533.g4f5dca5207-goog
reply other threads:[~2026-04-21 14:25 UTC|newest]
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