Vladimir Oltean a13e690191 net/sched: sch_api: fix xa_insert() error path in tcf_block_get_ext() ... This command: $ tc qdisc replace dev eth0 ingress_block 1 egress_block 1 clsact Error: block dev insert failed: -EBUSY. fails because user space requests the same block index to be set for both ingress and egress. [ side note, I don't think it even failed prior to commit 913b47d342 ("net/sched: Introduce tc block netdev tracking infra"), because this is a command from an old set of notes of mine which used to work, but alas, I did not scientifically bisect this ] The problem is not that it fails, but rather, that the second time around, it fails differently (and irrecoverably): $ tc qdisc replace dev eth0 ingress_block 1 egress_block 1 clsact Error: dsa_core: Flow block cb is busy. [ another note: the extack is added by me for illustration purposes. the context of the problem is that clsact_init() obtains the same &q->ingress_block pointer as &q->egress_block, and since we call tcf_block_get_ext() on both of them, "dev" will be added to the block->ports xarray twice, thus failing the operation: once through the ingress block pointer, and once again through the egress block pointer. the problem itself is that when xa_insert() fails, we have emitted a FLOW_BLOCK_BIND command through ndo_setup_tc(), but the offload never sees a corresponding FLOW_BLOCK_UNBIND. ] Even correcting the bad user input, we still cannot recover: $ tc qdisc replace dev swp3 ingress_block 1 egress_block 2 clsact Error: dsa_core: Flow block cb is busy. Basically the only way to recover is to reboot the system, or unbind and rebind the net device driver. To fix the bug, we need to fill the correct error teardown path which was missed during code movement, and call tcf_block_offload_unbind() when xa_insert() fails. [ last note, fundamentally I blame the label naming convention in tcf_block_get_ext() for the bug. The labels should be named after what they do, not after the error path that jumps to them. This way, it is obviously wrong that two labels pointing to the same code mean something is wrong, and checking the code correctness at the goto site is also easier ] Fixes: 94e2557d08 ("net: sched: move block device tracking into tcf_block_get/put_ext()") Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Simon Horman <horms@kernel.org> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://patch.msgid.link/20241023100541.974362-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>		2024-10-29 11:45:23 -07:00
..
act_api.c	net/sched: act_api: deny mismatched skip_sw/skip_hw flags for actions created by classifiers	2024-10-23 11:31:27 +02:00
act_bpf.c	net: Rename mono_delivery_time to tstamp_type for scalabilty	2024-05-23 14:14:23 -07:00
act_connmark.c
act_csum.c
act_ct.c	sched: act_ct: avoid -Wflex-array-member-not-at-end warning	2024-08-12 17:54:24 -07:00
act_ctinfo.c
act_gact.c
act_gate.c
act_ife.c
act_meta_mark.c
act_meta_skbprio.c
act_meta_skbtcindex.c
act_mirred.c
act_mpls.c
act_nat.c
act_pedit.c
act_police.c
act_sample.c	net: sched: act_sample: add action cookie to sample	2024-07-05 17:45:47 -07:00
act_simple.c
act_skbedit.c
act_skbmod.c	net/sched: act_skbmod: convert comma to semicolon	2024-07-11 17:12:15 -07:00
act_tunnel_key.c
act_vlan.c	tc: adjust network header after 2nd vlan push	2024-08-27 11:37:42 +02:00
cls_api.c	net/sched: sch_api: fix xa_insert() error path in tcf_block_get_ext()	2024-10-29 11:45:23 -07:00
cls_basic.c
cls_bpf.c	net: Rename mono_delivery_time to tstamp_type for scalabilty	2024-05-23 14:14:23 -07:00
cls_cgroup.c
cls_flow.c
cls_flower.c	net/sched: cls_flower: propagate tca[TCA_OPTIONS] to NL_REQ_ATTR_CHECK	2024-07-15 09:14:39 -07:00
cls_fw.c
cls_matchall.c
cls_route.c
cls_u32.c
em_canid.c
em_cmp.c	move asm/unaligned.h to linux/unaligned.h	2024-10-02 17:23:23 -04:00
em_ipset.c
em_ipt.c
em_meta.c
em_nbyte.c
em_text.c
em_u32.c
ematch.c
Kconfig
Makefile
sch_api.c	net/sched: stop qdisc_tree_reduce_backlog on TC_H_ROOT	2024-10-29 11:32:26 -07:00
sch_blackhole.c
sch_cake.c	sch_cake: constify inverse square root cache	2024-09-10 18:31:52 -07:00
sch_cbs.c
sch_choke.c
sch_codel.c
sch_drr.c
sch_etf.c
sch_ets.c
sch_fifo.c
sch_fq.c	net_sched: sch_fq: fix incorrect behavior for small weights	2024-08-27 08:20:45 -07:00
sch_fq_codel.c
sch_fq_pie.c
sch_frag.c
sch_generic.c	net: fix races in netdev_tx_sent_queue()/dev_watchdog()	2024-10-21 12:54:25 +02:00
sch_gred.c
sch_hfsc.c
sch_hhf.c
sch_htb.c
sch_ingress.c	bpf: Fix too early release of tcx_entry	2024-07-08 14:07:31 -07:00
sch_mq.c
sch_mqprio.c
sch_mqprio_lib.c
sch_mqprio_lib.h
sch_multiq.c	net: sched: sch_multiq: fix possible OOB write in multiq_tune()	2024-06-05 10:50:19 +01:00
sch_netem.c	sch/netem: fix use after free in netem_dequeue	2024-09-03 11:44:23 -07:00
sch_pie.c
sch_plug.c
sch_prio.c
sch_qfq.c
sch_red.c
sch_sfb.c
sch_sfq.c	net_sched: sch_sfq: annotate data-races around q->perturb_period	2024-05-02 19:01:35 -07:00
sch_skbprio.c
sch_taprio.c	net: sched: use RCU read-side critical section in taprio_dump()	2024-10-23 13:26:15 +02:00
sch_tbf.c
sch_teql.c	net: annotate writes on dev->mtu from ndo_change_mtu()	2024-05-07 16:19:14 -07:00