net: sched: avoid duplicates in qdisc dump
tc_dump_qdisc() performs dumping of the per-device qdiscs in two phases; first, the "standard" dev->qdisc is being dumped. Second, if there is/are ingress queue(s), they are being dumped as well. After conversion of netdevice's qdisc linked-list into hashtable, these two sets are not in two disjunctive sets/lists any more, but are both "reachable" directly from netdevice's hashtable. As a consequence, the "full-depth" dump of the ingress qdiscs results in immediately hitting the netdevice hashtable again, and duplicating the dump that has already been performed for dev->qdisc. What in fact needs to be dumped in case of ingress queue is "just" the top-level ingress qdisc, as everything else has been dumped already. Fix this by extending tc_dump_qdisc_root() in a way that it can be instructed whether it should (while performing the "full" per-netdev qdisc dump) perform the whole recursion, or just dump "additional" top-level (ingress) qdiscs without performing any kind of recursion. This fixes duplicate dumps such as qdisc mq 0: root qdisc pfifo_fast 0: parent :4 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :3 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc clsact ffff: parent ffff:fff1 qdisc pfifo_fast 0: parent :4 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :3 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :2 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 qdisc pfifo_fast 0: parent :1 bands 3 priomap 1 2 2 2 1 2 0 0 1 1 1 1 1 1 1 1 Fixes: 59cc1f61 ("net: sched: convert qdisc linked list to hashtable") Reported-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
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