From 3c53ed8fef6881a864f0ee8240ed2793ef73ad0d Mon Sep 17 00:00:00 2001 From: Phil Sutter Date: Thu, 18 Oct 2018 10:34:26 +0200 Subject: [PATCH] net: sched: Fix for duplicate class dump When dumping classes by parent, kernel would return classes twice: | # tc qdisc add dev lo root prio | # tc class show dev lo | class prio 8001:1 parent 8001: | class prio 8001:2 parent 8001: | class prio 8001:3 parent 8001: | # tc class show dev lo parent 8001: | class prio 8001:1 parent 8001: | class prio 8001:2 parent 8001: | class prio 8001:3 parent 8001: | class prio 8001:1 parent 8001: | class prio 8001:2 parent 8001: | class prio 8001:3 parent 8001: This comes from qdisc_match_from_root() potentially returning the root qdisc itself if its handle matched. Though in that case, root's classes were already dumped a few lines above. Fixes: cb395b2010879 ("net: sched: optimize class dumps") Signed-off-by: Phil Sutter Reviewed-by: Jiri Pirko Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_api.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 6684641ea344..3dc0acf54245 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -2059,7 +2059,8 @@ static int tc_dump_tclass_root(struct Qdisc *root, struct sk_buff *skb, if (tcm->tcm_parent) { q = qdisc_match_from_root(root, TC_H_MAJ(tcm->tcm_parent)); - if (q && tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0) + if (q && q != root && + tc_dump_tclass_qdisc(q, skb, tcm, cb, t_p, s_t) < 0) return -1; return 0; }