linux/net
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
..
6lowpan ipv6: eliminate ndisc_ops_is_useropt() 2024-08-12 17:23:57 -07:00
9p 9p: fix slab cache name creation for real 2024-10-21 15:41:29 -07:00
802 move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
8021q netdev_features: remove NETIF_F_ALL_FCOE 2024-09-03 11:36:43 +02:00
appletalk
atm atm: clean up a put_user() calls 2024-06-14 19:08:50 -07:00
ax25 ax25: Replace kfree() in ax25_dev_free() with ax25_dev_put() 2024-06-01 15:49:42 -07:00
batman-adv move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
bluetooth Including fixes from netfiler, xfrm and bluetooth. 2024-10-24 16:43:50 -07:00
bpf bpf: use type_may_be_null() helper for nullable-param check 2024-09-05 13:29:06 -07:00
bridge bridge: Handle error of rtnl_register_module(). 2024-10-10 15:39:35 +02:00
caif move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
can Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-15 09:13:19 -07:00
ceph libceph: use min() to simplify code in ceph_dns_resolve_name() 2024-08-27 09:30:16 +02:00
core BPF fixes: 2024-10-18 16:27:14 -07:00
dcb
dccp move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
devlink devlink: Constify the 'table_ops' parameter of devl_dpipe_table_register() 2024-06-05 10:24:57 +01:00
dns_resolver
dsa net: dsa: refuse cross-chip mirroring operations 2024-10-09 19:41:35 -07:00
ethernet netkit: Fix pkt_type override upon netkit pass verdict 2024-05-25 10:48:57 -07:00
ethtool net: ethtool: phy: Don't set the context dev pointer for unfiltered DUMP 2024-09-13 21:40:12 -07:00
handshake net/handshake: use sockfd_put() helper 2024-08-27 16:09:25 -07:00
hsr Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-12 17:11:24 -07:00
ieee802154 netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_local 2024-09-03 11:36:43 +02:00
ife
ipv4 ipv4: ip_tunnel: Fix suspicious RCU usage warning in ip_tunnel_find() 2024-10-29 11:12:53 -07:00
ipv6 ipsec-2024-10-22 2024-10-24 11:11:33 +02:00
iucv s390/iucv: Fix vargs handling in iucv_alloc_device() 2024-08-22 13:09:20 -07:00
kcm kcm: Serialise kcm_sendmsg() for the same socket. 2024-08-19 18:36:12 -07:00
key
l2tp genetlink: hold RCU in genlmsg_mcast() 2024-10-15 17:52:58 -07:00
l3mdev
lapb
llc llc: Constify struct llc_sap_state_trans 2024-07-15 08:51:19 -07:00
mac80211 wireless fixes for v6.12-rc5 2024-10-25 10:44:41 +01:00
mac802154 Including fixes from ieee802154, bluetooth and netfilter. 2024-10-03 09:44:00 -07:00
mctp mctp: Handle error of rtnl_register_module(). 2024-10-10 15:39:35 +02:00
mpls mpls: Handle error of rtnl_register_module(). 2024-10-10 15:39:35 +02:00
mptcp mptcp: init: protect sched with rcu_read_lock 2024-10-28 15:50:54 -07:00
ncsi net/ncsi: Disable the ncsi work before freeing the associated structure 2024-10-03 10:14:14 +02:00
netfilter Including fixes from netfiler, xfrm and bluetooth. 2024-10-24 16:43:50 -07:00
netlabel
netlink genetlink: hold RCU in genlmsg_mcast() 2024-10-15 17:52:58 -07:00
netrom net/netrom: prefer strscpy over strcpy 2024-08-29 12:33:07 -07:00
nfc Quite smaller than usual. Notably it includes the fix for the unix 2024-05-23 12:49:37 -07:00
nsh
openvswitch netdev_features: convert NETIF_F_NETNS_LOCAL to dev->netns_local 2024-09-03 11:36:43 +02:00
packet net: add support for skbs with unreadable frags 2024-09-11 20:44:31 -07:00
phonet phonet: Handle error of rtnl_register_module(). 2024-10-10 15:39:36 +02:00
psample net: psample: fix flag being set in wrong skb 2024-07-11 18:11:31 -07:00
qrtr net: qrtr: Update packets cloning when broadcasting 2024-09-24 10:48:16 +02:00
rds net: rds: add option for GCOV profiling 2024-08-09 13:18:46 +01:00
rfkill [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
rose
rxrpc rxrpc: Fix uninitialised variable in rxrpc_send_data() 2024-10-03 16:23:21 -07:00
sched net/sched: sch_api: fix xa_insert() error path in tcf_block_get_ext() 2024-10-29 11:45:23 -07:00
sctp sctp: ensure sk_state is set to CLOSED if hashing fails in sctp_listen_start 2024-10-09 13:36:32 +01:00
smc net/smc: Fix searching in list of known pnetids in smc_pnet_add_pnetid 2024-10-15 10:56:31 -07:00
strparser
sunrpc NFS Client Bugfixes for Linux 6.12-rc 2024-10-11 15:37:15 -07:00
switchdev
tipc Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2024-09-15 09:13:19 -07:00
tls move asm/unaligned.h to linux/unaligned.h 2024-10-02 17:23:23 -04:00
unix af_unix: Don't return OOB skb in manage_oob(). 2024-09-09 17:14:27 -07:00
vmw_vsock BPF fixes: 2024-10-18 16:27:14 -07:00
wireless wireless fixes for v6.12-rc5 2024-10-25 10:44:41 +01:00
x25
xdp bpf-next-6.12 2024-09-21 09:27:50 -07:00
xfrm ipsec-2024-10-22 2024-10-24 11:11:33 +02:00
compat.c
devres.c
Kconfig memory-provider: disable building dmabuf mp on !CONFIG_PAGE_POOL 2024-09-13 11:41:45 -07:00
Kconfig.debug
Makefile
socket.c net: explicitly clear the sk pointer, when pf->create fails 2024-10-07 16:21:59 -07:00
sysctl_net.c sysctl: Remove check for sentinel element in ctl_table arrays 2024-06-13 10:50:52 +02:00