| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 136/143] net: sched: Fix for duplicate class dump | Date | Fri, 2 Nov 2018 19:35:21 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Phil Sutter <phil@nwl.cc>
[ Upstream commit 3c53ed8fef6881a864f0ee8240ed2793ef73ad0d ]
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 <phil@nwl.cc> Reviewed-by: Jiri Pirko <jiri@mellanox.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/sched/sch_api.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -1917,7 +1917,8 @@ static int tc_dump_tclass_root(struct Qd 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; }
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