linux-stable.git/net/openvswitch, branch v5.15.208

openvswitch: validate MPLS set/set_masked payload length

2026-04-18T08:33:24+00:00

[ Upstream commit 546b68ac893595877ffbd7751e5c55fd1c43ede6 ]

validate_set() accepted OVS_KEY_ATTR_MPLS as variable-sized payload for
SET/SET_MASKED actions. In action handling, OVS expects fixed-size
MPLS key data (struct ovs_key_mpls).

Use the already normalized key_len (masked case included) and reject
non-matching MPLS action key sizes.

Reject invalid MPLS action payload lengths early.

Fixes: fbdcdd78da7c ("Change in Openvswitch to support MPLS label depth of 3 in ingress direction")
Reported-by: Yifan Wu 
Reported-by: Juefei Pu 
Tested-by: Ao Zhou 
Co-developed-by: Yuan Tan 
Signed-off-by: Yuan Tan 
Suggested-by: Xin Liu 
Signed-off-by: Yang Yang 
Reviewed-by: Ilya Maximets 
Link: https://patch.msgid.link/20260319080228.3423307-1-n05ec@lzu.edu.cn
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: openvswitch: Avoid releasing netdev before teardown completes

2026-04-18T08:33:24+00:00

[ Upstream commit 7c770dadfda5cbbde6aa3c4363ed513f1d212bf8 ]

The patch cited in the Fixes tag below changed the teardown code for
OVS ports to no longer unconditionally take the RTNL. After this change,
the netdev_destroy() callback can proceed immediately to the call_rcu()
invocation if the IFF_OVS_DATAPATH flag is already cleared on the
netdev.

The ovs_netdev_detach_dev() function clears the flag before completing
the unregistration, and if it gets preempted after clearing the flag (as
can happen on an -rt kernel), netdev_destroy() can complete and the
device can be freed before the unregistration completes. This leads to a
splat like:

[  998.393867] Oops: general protection fault, probably for non-canonical address 0xff00000001000239: 0000 [#1] SMP PTI
[  998.393877] CPU: 42 UID: 0 PID: 55177 Comm: ip Kdump: loaded Not tainted 6.12.0-211.1.1.el10_2.x86_64+rt #1 PREEMPT_RT
[  998.393886] Hardware name: Dell Inc. PowerEdge R740/0JMK61, BIOS 2.24.0 03/27/2025
[  998.393889] RIP: 0010:dev_set_promiscuity+0x8d/0xa0
[  998.393901] Code: 00 00 75 d8 48 8b 53 08 48 83 ba b0 02 00 00 00 75 ca 48 83 c4 08 5b c3 cc cc cc cc 48 83 bf 48 09 00 00 00 75 91 48 8b 47 08 <48> 83 b8 b0 02 00 00 00 74 97 eb 81 0f 1f 80 00 00 00 00 90 90 90
[  998.393906] RSP: 0018:ffffce5864a5f6a0 EFLAGS: 00010246
[  998.393912] RAX: ff00000000ffff89 RBX: ffff894d0adf5a05 RCX: 0000000000000000
[  998.393917] RDX: 0000000000000000 RSI: 00000000ffffffff RDI: ffff894d0adf5a05
[  998.393921] RBP: ffff894d19252000 R08: ffff894d19252000 R09: 0000000000000000
[  998.393924] R10: ffff894d19252000 R11: ffff894d192521b8 R12: 0000000000000006
[  998.393927] R13: ffffce5864a5f738 R14: 00000000ffffffe2 R15: 0000000000000000
[  998.393931] FS:  00007fad61971800(0000) GS:ffff894cc0140000(0000) knlGS:0000000000000000
[  998.393936] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  998.393940] CR2: 000055df0a2a6e40 CR3: 000000011c7fe003 CR4: 00000000007726f0
[  998.393944] PKRU: 55555554
[  998.393946] Call Trace:
[  998.393949]  
[  998.393952]  ? show_trace_log_lvl+0x1b0/0x2f0
[  998.393961]  ? show_trace_log_lvl+0x1b0/0x2f0
[  998.393975]  ? dp_device_event+0x41/0x80 [openvswitch]
[  998.394009]  ? __die_body.cold+0x8/0x12
[  998.394016]  ? die_addr+0x3c/0x60
[  998.394027]  ? exc_general_protection+0x16d/0x390
[  998.394042]  ? asm_exc_general_protection+0x26/0x30
[  998.394058]  ? dev_set_promiscuity+0x8d/0xa0
[  998.394066]  ? ovs_netdev_detach_dev+0x3a/0x80 [openvswitch]
[  998.394092]  dp_device_event+0x41/0x80 [openvswitch]
[  998.394102]  notifier_call_chain+0x5a/0xd0
[  998.394106]  unregister_netdevice_many_notify+0x51b/0xa60
[  998.394110]  rtnl_dellink+0x169/0x3e0
[  998.394121]  ? rt_mutex_slowlock.constprop.0+0x95/0xd0
[  998.394125]  rtnetlink_rcv_msg+0x142/0x3f0
[  998.394128]  ? avc_has_perm_noaudit+0x69/0xf0
[  998.394130]  ? __pfx_rtnetlink_rcv_msg+0x10/0x10
[  998.394132]  netlink_rcv_skb+0x50/0x100
[  998.394138]  netlink_unicast+0x292/0x3f0
[  998.394141]  netlink_sendmsg+0x21b/0x470
[  998.394145]  ____sys_sendmsg+0x39d/0x3d0
[  998.394149]  ___sys_sendmsg+0x9a/0xe0
[  998.394156]  __sys_sendmsg+0x7a/0xd0
[  998.394160]  do_syscall_64+0x7f/0x170
[  998.394162]  entry_SYSCALL_64_after_hwframe+0x76/0x7e
[  998.394165] RIP: 0033:0x7fad61bf4724
[  998.394188] Code: 89 02 b8 ff ff ff ff eb bb 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 f3 0f 1e fa 80 3d c5 e9 0c 00 00 74 13 b8 2e 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 48 83 ec 28 89 54 24 1c 48 89
[  998.394189] RSP: 002b:00007ffd7e2f7cb8 EFLAGS: 00000202 ORIG_RAX: 000000000000002e
[  998.394191] RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007fad61bf4724
[  998.394193] RDX: 0000000000000000 RSI: 00007ffd7e2f7d20 RDI: 0000000000000003
[  998.394194] RBP: 00007ffd7e2f7d90 R08: 0000000000000010 R09: 000000000000003f
[  998.394195] R10: 000055df11558010 R11: 0000000000000202 R12: 00007ffd7e2f8380
[  998.394196] R13: 0000000069b233d7 R14: 000055df0a256040 R15: 0000000000000000
[  998.394200]  

To fix this, reorder the operations in ovs_netdev_detach_dev() to only
clear the flag after completing the other operations, and introduce an
smp_wmb() to make the ordering requirement explicit. The smp_wmb() is
paired with a full smp_mb() in netdev_destroy() to make sure the
call_rcu() invocation does not happen before the unregister operations
are visible.

Reported-by: Minxi Hou 
Tested-by: Minxi Hou 
Fixes: 549822767630 ("net: openvswitch: Avoid needlessly taking the RTNL on vport destroy")
Signed-off-by: Toke Høiland-Jørgensen 
Link: https://patch.msgid.link/20260318155554.1133405-1-toke@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: openvswitch: Avoid needlessly taking the RTNL on vport destroy

2026-01-19T12:09:56+00:00

[ Upstream commit 5498227676303e3ffa9a3a46214af96bc3e81314 ]

The openvswitch teardown code will immediately call
ovs_netdev_detach_dev() in response to a NETDEV_UNREGISTER notification.
It will then start the dp_notify_work workqueue, which will later end up
calling the vport destroy() callback. This callback takes the RTNL to do
another ovs_netdev_detach_port(), which in this case is unnecessary.
This causes extra pressure on the RTNL, in some cases leading to
"unregister_netdevice: waiting for XX to become free" warnings on
teardown.

We can straight-forwardly avoid the extra RTNL lock acquisition by
checking the device flags before taking the lock, and skip the locking
altogether if the IFF_OVS_DATAPATH flag has already been unset.

Fixes: b07c26511e94 ("openvswitch: fix vport-netdev unregister")
Tested-by: Adrian Moreno 
Signed-off-by: Toke Høiland-Jørgensen 
Acked-by: Eelco Chaudron 
Acked-by: Aaron Conole 
Link: https://patch.msgid.link/20251211115006.228876-1-toke@redhat.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

net: openvswitch: fix middle attribute validation in push_nsh() action

2026-01-19T12:09:43+00:00

[ Upstream commit 5ace7ef87f059d68b5f50837ef3e8a1a4870c36e ]

The push_nsh() action structure looks like this:

 OVS_ACTION_ATTR_PUSH_NSH(OVS_KEY_ATTR_NSH(OVS_NSH_KEY_ATTR_BASE,...))

The outermost OVS_ACTION_ATTR_PUSH_NSH attribute is OK'ed by the
nla_for_each_nested() inside __ovs_nla_copy_actions().  The innermost
OVS_NSH_KEY_ATTR_BASE/MD1/MD2 are OK'ed by the nla_for_each_nested()
inside nsh_key_put_from_nlattr().  But nothing checks if the attribute
in the middle is OK.  We don't even check that this attribute is the
OVS_KEY_ATTR_NSH.  We just do a double unwrap with a pair of nla_data()
calls - first time directly while calling validate_push_nsh() and the
second time as part of the nla_for_each_nested() macro, which isn't
safe, potentially causing invalid memory access if the size of this
attribute is incorrect.  The failure may not be noticed during
validation due to larger netlink buffer, but cause trouble later during
action execution where the buffer is allocated exactly to the size:

 BUG: KASAN: slab-out-of-bounds in nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
 Read of size 184 at addr ffff88816459a634 by task a.out/22624

 CPU: 8 UID: 0 PID: 22624 6.18.0-rc7+ #115 PREEMPT(voluntary)
 Call Trace:
  
  dump_stack_lvl+0x51/0x70
  print_address_description.constprop.0+0x2c/0x390
  kasan_report+0xdd/0x110
  kasan_check_range+0x35/0x1b0
  __asan_memcpy+0x20/0x60
  nsh_hdr_from_nlattr+0x1dd/0x6a0 [openvswitch]
  push_nsh+0x82/0x120 [openvswitch]
  do_execute_actions+0x1405/0x2840 [openvswitch]
  ovs_execute_actions+0xd5/0x3b0 [openvswitch]
  ovs_packet_cmd_execute+0x949/0xdb0 [openvswitch]
  genl_family_rcv_msg_doit+0x1d6/0x2b0
  genl_family_rcv_msg+0x336/0x580
  genl_rcv_msg+0x9f/0x130
  netlink_rcv_skb+0x11f/0x370
  genl_rcv+0x24/0x40
  netlink_unicast+0x73e/0xaa0
  netlink_sendmsg+0x744/0xbf0
  __sys_sendto+0x3d6/0x450
  do_syscall_64+0x79/0x2c0
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
  

Let's add some checks that the attribute is properly sized and it's
the only one attribute inside the action.  Technically, there is no
real reason for OVS_KEY_ATTR_NSH to be there, as we know that we're
pushing an NSH header already, it just creates extra nesting, but
that's how uAPI works today.  So, keeping as it is.

Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support")
Reported-by: Junvy Yang 
Signed-off-by: Ilya Maximets 
Acked-by: Eelco Chaudron echaudro@redhat.com
Reviewed-by: Aaron Conole 
Link: https://patch.msgid.link/20251204105334.900379-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

netfilter: nf_conncount: rework API to use sk_buff directly

2026-01-19T12:09:35+00:00

[ Upstream commit be102eb6a0e7c03db00e50540622f4e43b2d2844 ]

When using nf_conncount infrastructure for non-confirmed connections a
duplicated track is possible due to an optimization introduced since
commit d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC").

In order to fix this introduce a new conncount API that receives
directly an sk_buff struct.  It fetches the tuple and zone and the
corresponding ct from it. It comes with both existing conncount variants
nf_conncount_count_skb() and nf_conncount_add_skb(). In addition remove
the old API and adjust all the users to use the new one.

This way, for each sk_buff struct it is possible to check if there is a
ct present and already confirmed. If so, skip the add operation.

Fixes: d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC")
Signed-off-by: Fernando Fernandez Mancera 
Signed-off-by: Pablo Neira Ayuso 
Stable-dep-of: 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped")
Signed-off-by: Sasha Levin

net: openvswitch: remove never-working support for setting nsh fields

2025-12-06T21:09:31+00:00

[ Upstream commit dfe28c4167a9259fc0c372d9f9473e1ac95cff67 ]

The validation of the set(nsh(...)) action is completely wrong.
It runs through the nsh_key_put_from_nlattr() function that is the
same function that validates NSH keys for the flow match and the
push_nsh() action.  However, the set(nsh(...)) has a very different
memory layout.  Nested attributes in there are doubled in size in
case of the masked set().  That makes proper validation impossible.

There is also confusion in the code between the 'masked' flag, that
says that the nested attributes are doubled in size containing both
the value and the mask, and the 'is_mask' that says that the value
we're parsing is the mask.  This is causing kernel crash on trying to
write into mask part of the match with SW_FLOW_KEY_PUT() during
validation, while validate_nsh() doesn't allocate any memory for it:

  BUG: kernel NULL pointer dereference, address: 0000000000000018
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 1c2383067 P4D 1c2383067 PUD 20b703067 PMD 0
  Oops: Oops: 0000 [#1] SMP NOPTI
  CPU: 8 UID: 0 Kdump: loaded Not tainted 6.17.0-rc4+ #107 PREEMPT(voluntary)
  RIP: 0010:nsh_key_put_from_nlattr+0x19d/0x610 [openvswitch]
  Call Trace:
   
   validate_nsh+0x60/0x90 [openvswitch]
   validate_set.constprop.0+0x270/0x3c0 [openvswitch]
   __ovs_nla_copy_actions+0x477/0x860 [openvswitch]
   ovs_nla_copy_actions+0x8d/0x100 [openvswitch]
   ovs_packet_cmd_execute+0x1cc/0x310 [openvswitch]
   genl_family_rcv_msg_doit+0xdb/0x130
   genl_family_rcv_msg+0x14b/0x220
   genl_rcv_msg+0x47/0xa0
   netlink_rcv_skb+0x53/0x100
   genl_rcv+0x24/0x40
   netlink_unicast+0x280/0x3b0
   netlink_sendmsg+0x1f7/0x430
   ____sys_sendmsg+0x36b/0x3a0
   ___sys_sendmsg+0x87/0xd0
   __sys_sendmsg+0x6d/0xd0
   do_syscall_64+0x7b/0x2c0
   entry_SYSCALL_64_after_hwframe+0x76/0x7e

The third issue with this process is that while trying to convert
the non-masked set into masked one, validate_set() copies and doubles
the size of the OVS_KEY_ATTR_NSH as if it didn't have any nested
attributes.  It should be copying each nested attribute and doubling
them in size independently.  And the process must be properly reversed
during the conversion back from masked to a non-masked variant during
the flow dump.

In the end, the only two outcomes of trying to use this action are
either validation failure or a kernel crash.  And if somehow someone
manages to install a flow with such an action, it will most definitely
not do what it is supposed to, since all the keys and the masks are
mixed up.

Fixing all the issues is a complex task as it requires re-writing
most of the validation code.

Given that and the fact that this functionality never worked since
introduction, let's just remove it altogether.  It's better to
re-introduce it later with a proper implementation instead of trying
to fix it in stable releases.

Fixes: b2d0f5d5dc53 ("openvswitch: enable NSH support")
Reported-by: Junvy Yang 
Signed-off-by: Ilya Maximets 
Acked-by: Eelco Chaudron 
Reviewed-by: Aaron Conole 
Link: https://patch.msgid.link/20251112112246.95064-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin

net: openvswitch: Fix the dead loop of MPLS parse

2025-06-27T10:05:14+00:00

[ Upstream commit 0bdc924bfb319fb10d1113cbf091fc26fb7b1f99 ]

The unexpected MPLS packet may not end with the bottom label stack.
When there are many stacks, The label count value has wrapped around.
A dead loop occurs, soft lockup/CPU stuck finally.

stack backtrace:
UBSAN: array-index-out-of-bounds in /build/linux-0Pa0xK/linux-5.15.0/net/openvswitch/flow.c:662:26
index -1 is out of range for type '__be32 [3]'
CPU: 34 PID: 0 Comm: swapper/34 Kdump: loaded Tainted: G           OE   5.15.0-121-generic #131-Ubuntu
Hardware name: Dell Inc. PowerEdge C6420/0JP9TF, BIOS 2.12.2 07/14/2021
Call Trace:
 
 show_stack+0x52/0x5c
 dump_stack_lvl+0x4a/0x63
 dump_stack+0x10/0x16
 ubsan_epilogue+0x9/0x36
 __ubsan_handle_out_of_bounds.cold+0x44/0x49
 key_extract_l3l4+0x82a/0x840 [openvswitch]
 ? kfree_skbmem+0x52/0xa0
 key_extract+0x9c/0x2b0 [openvswitch]
 ovs_flow_key_extract+0x124/0x350 [openvswitch]
 ovs_vport_receive+0x61/0xd0 [openvswitch]
 ? kernel_init_free_pages.part.0+0x4a/0x70
 ? get_page_from_freelist+0x353/0x540
 netdev_port_receive+0xc4/0x180 [openvswitch]
 ? netdev_port_receive+0x180/0x180 [openvswitch]
 netdev_frame_hook+0x1f/0x40 [openvswitch]
 __netif_receive_skb_core.constprop.0+0x23a/0xf00
 __netif_receive_skb_list_core+0xfa/0x240
 netif_receive_skb_list_internal+0x18e/0x2a0
 napi_complete_done+0x7a/0x1c0
 bnxt_poll+0x155/0x1c0 [bnxt_en]
 __napi_poll+0x30/0x180
 net_rx_action+0x126/0x280
 ? bnxt_msix+0x67/0x80 [bnxt_en]
 handle_softirqs+0xda/0x2d0
 irq_exit_rcu+0x96/0xc0
 common_interrupt+0x8e/0xa0
 

Fixes: fbdcdd78da7c ("Change in Openvswitch to support MPLS label depth of 3 in ingress direction")
Signed-off-by: Faicker Mo 
Acked-by: Ilya Maximets 
Reviewed-by: Aaron Conole 
Link: https://patch.msgid.link/259D3404-575D-4A6D-B263-1DF59A67CF89@zenlayer.com
Signed-off-by: Paolo Abeni 
Signed-off-by: Sasha Levin

openvswitch: Fix unsafe attribute parsing in output_userspace()

2025-05-18T06:20:35+00:00

commit 6beb6835c1fbb3f676aebb51a5fee6b77fed9308 upstream.

This patch replaces the manual Netlink attribute iteration in
output_userspace() with nla_for_each_nested(), which ensures that only
well-formed attributes are processed.

Fixes: ccb1352e76cf ("net: Add Open vSwitch kernel components.")
Signed-off-by: Eelco Chaudron 
Acked-by: Ilya Maximets 
Acked-by: Aaron Conole 
Link: https://patch.msgid.link/0bd65949df61591d9171c0dc13e42cea8941da10.1746541734.git.echaudro@redhat.com
Signed-off-by: Jakub Kicinski 
Signed-off-by: Greg Kroah-Hartman

openvswitch: fix lockup on tx to unregistering netdev with carrier

2025-05-02T05:44:22+00:00

commit 47e55e4b410f7d552e43011baa5be1aab4093990 upstream.

Commit in a fixes tag attempted to fix the issue in the following
sequence of calls:

    do_output
    -> ovs_vport_send
       -> dev_queue_xmit
          -> __dev_queue_xmit
             -> netdev_core_pick_tx
                -> skb_tx_hash

When device is unregistering, the 'dev->real_num_tx_queues' goes to
zero and the 'while (unlikely(hash >= qcount))' loop inside the
'skb_tx_hash' becomes infinite, locking up the core forever.

But unfortunately, checking just the carrier status is not enough to
fix the issue, because some devices may still be in unregistering
state while reporting carrier status OK.

One example of such device is a net/dummy.  It sets carrier ON
on start, but it doesn't implement .ndo_stop to set the carrier off.
And it makes sense, because dummy doesn't really have a carrier.
Therefore, while this device is unregistering, it's still easy to hit
the infinite loop in the skb_tx_hash() from the OVS datapath.  There
might be other drivers that do the same, but dummy by itself is
important for the OVS ecosystem, because it is frequently used as a
packet sink for tcpdump while debugging OVS deployments.  And when the
issue is hit, the only way to recover is to reboot.

Fix that by also checking if the device is running.  The running
state is handled by the net core during unregistering, so it covers
unregistering case better, and we don't really need to send packets
to devices that are not running anyway.

While only checking the running state might be enough, the carrier
check is preserved.  The running and the carrier states seem disjoined
throughout the code and different drivers.  And other core functions
like __dev_direct_xmit() check both before attempting to transmit
a packet.  So, it seems safer to check both flags in OVS as well.

Fixes: 066b86787fa3 ("net: openvswitch: fix race on port output")
Reported-by: Friedrich Weber 
Closes: https://mail.openvswitch.org/pipermail/ovs-discuss/2025-January/053423.html
Signed-off-by: Ilya Maximets 
Tested-by: Friedrich Weber 
Reviewed-by: Aaron Conole 
Link: https://patch.msgid.link/20250109122225.4034688-1-i.maximets@ovn.org
Signed-off-by: Jakub Kicinski 
Signed-off-by: Sasha Levin 
Signed-off-by: Carlos Soto 
Signed-off-by: Florian Fainelli 
Signed-off-by: Greg Kroah-Hartman

net: openvswitch: fix race on port output

2025-05-02T05:44:22+00:00

commit 066b86787fa3d97b7aefb5ac0a99a22dad2d15f8 upstream.

assume the following setup on a single machine:
1. An openvswitch instance with one bridge and default flows
2. two network namespaces "server" and "client"
3. two ovs interfaces "server" and "client" on the bridge
4. for each ovs interface a veth pair with a matching name and 32 rx and
   tx queues
5. move the ends of the veth pairs to the respective network namespaces
6. assign ip addresses to each of the veth ends in the namespaces (needs
   to be the same subnet)
7. start some http server on the server network namespace
8. test if a client in the client namespace can reach the http server

when following the actions below the host has a chance of getting a cpu
stuck in a infinite loop:
1. send a large amount of parallel requests to the http server (around
   3000 curls should work)
2. in parallel delete the network namespace (do not delete interfaces or
   stop the server, just kill the namespace)

there is a low chance that this will cause the below kernel cpu stuck
message. If this does not happen just retry.
Below there is also the output of bpftrace for the functions mentioned
in the output.

The series of events happening here is:
1. the network namespace is deleted calling
   `unregister_netdevice_many_notify` somewhere in the process
2. this sets first `NETREG_UNREGISTERING` on both ends of the veth and
   then runs `synchronize_net`
3. it then calls `call_netdevice_notifiers` with `NETDEV_UNREGISTER`
4. this is then handled by `dp_device_event` which calls
   `ovs_netdev_detach_dev` (if a vport is found, which is the case for
   the veth interface attached to ovs)
5. this removes the rx_handlers of the device but does not prevent
   packages to be sent to the device
6. `dp_device_event` then queues the vport deletion to work in
   background as a ovs_lock is needed that we do not hold in the
   unregistration path
7. `unregister_netdevice_many_notify` continues to call
   `netdev_unregister_kobject` which sets `real_num_tx_queues` to 0
8. port deletion continues (but details are not relevant for this issue)
9. at some future point the background task deletes the vport

If after 7. but before 9. a packet is send to the ovs vport (which is
not deleted at this point in time) which forwards it to the
`dev_queue_xmit` flow even though the device is unregistering.
In `skb_tx_hash` (which is called in the `dev_queue_xmit`) path there is
a while loop (if the packet has a rx_queue recorded) that is infinite if
`dev->real_num_tx_queues` is zero.

To prevent this from happening we update `do_output` to handle devices
without carrier the same as if the device is not found (which would
be the code path after 9. is done).

Additionally we now produce a warning in `skb_tx_hash` if we will hit
the infinite loop.

bpftrace (first word is function name):

__dev_queue_xmit server: real_num_tx_queues: 1, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 1
netdev_core_pick_tx server: addr: 0xffff9f0a46d4a000 real_num_tx_queues: 1, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 1
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 2, reg_state: 1
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 6, reg_state: 2
ovs_netdev_detach_dev server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, reg_state: 2
netdev_rx_handler_unregister server: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024, reg_state: 2
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
netdev_rx_handler_unregister ret server: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024, reg_state: 2
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 27, reg_state: 2
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 22, reg_state: 2
dp_device_event server: real_num_tx_queues: 1 cpu 9, pid: 21024, tid: 21024, event 18, reg_state: 2
netdev_unregister_kobject: real_num_tx_queues: 1, cpu: 9, pid: 21024, tid: 21024
synchronize_rcu_expedited: cpu 9, pid: 21024, tid: 21024
ovs_vport_send server: real_num_tx_queues: 0, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 2
__dev_queue_xmit server: real_num_tx_queues: 0, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 2
netdev_core_pick_tx server: addr: 0xffff9f0a46d4a000 real_num_tx_queues: 0, cpu: 2, pid: 28024, tid: 28024, skb_addr: 0xffff9edb6f207000, reg_state: 2
broken device server: real_num_tx_queues: 0, cpu: 2, pid: 28024, tid: 28024
ovs_dp_detach_port server: real_num_tx_queues: 0 cpu 9, pid: 9124, tid: 9124, reg_state: 2
synchronize_rcu_expedited: cpu 9, pid: 33604, tid: 33604

stuck message:

watchdog: BUG: soft lockup - CPU#5 stuck for 26s! [curl:1929279]
Modules linked in: veth pktgen bridge stp llc ip_set_hash_net nft_counter xt_set nft_compat nf_tables ip_set_hash_ip ip_set nfnetlink_cttimeout nfnetlink openvswitch nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 tls binfmt_misc nls_iso8859_1 input_leds joydev serio_raw dm_multipath scsi_dh_rdac scsi_dh_emc scsi_dh_alua sch_fq_codel drm efi_pstore virtio_rng ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic usbhid hid crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel virtio_net ahci net_failover crypto_simd cryptd psmouse libahci virtio_blk failover
CPU: 5 PID: 1929279 Comm: curl Not tainted 5.15.0-67-generic #74-Ubuntu
Hardware name: OpenStack Foundation OpenStack Nova, BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:netdev_pick_tx+0xf1/0x320
Code: 00 00 8d 48 ff 0f b7 c1 66 39 ca 0f 86 e9 01 00 00 45 0f b7 ff 41 39 c7 0f 87 5b 01 00 00 44 29 f8 41 39 c7 0f 87 4f 01 00 00  f2 0f 1f 44 00 00 49 8b 94 24 28 04 00 00 48 85 d2 0f 84 53 01
RSP: 0018:ffffb78b40298820 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffff9c8773adc2e0 RCX: 000000000000083f
RDX: 0000000000000000 RSI: ffff9c8773adc2e0 RDI: ffff9c870a25e000
RBP: ffffb78b40298858 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff9c870a25e000
R13: ffff9c870a25e000 R14: ffff9c87fe043480 R15: 0000000000000000
FS:  00007f7b80008f00(0000) GS:ffff9c8e5f740000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7b80f6a0b0 CR3: 0000000329d66000 CR4: 0000000000350ee0
Call Trace:
 
 netdev_core_pick_tx+0xa4/0xb0
 __dev_queue_xmit+0xf8/0x510
 ? __bpf_prog_exit+0x1e/0x30
 dev_queue_xmit+0x10/0x20
 ovs_vport_send+0xad/0x170 [openvswitch]
 do_output+0x59/0x180 [openvswitch]
 do_execute_actions+0xa80/0xaa0 [openvswitch]
 ? kfree+0x1/0x250
 ? kfree+0x1/0x250
 ? kprobe_perf_func+0x4f/0x2b0
 ? flow_lookup.constprop.0+0x5c/0x110 [openvswitch]
 ovs_execute_actions+0x4c/0x120 [openvswitch]
 ovs_dp_process_packet+0xa1/0x200 [openvswitch]
 ? ovs_ct_update_key.isra.0+0xa8/0x120 [openvswitch]
 ? ovs_ct_fill_key+0x1d/0x30 [openvswitch]
 ? ovs_flow_key_extract+0x2db/0x350 [openvswitch]
 ovs_vport_receive+0x77/0xd0 [openvswitch]
 ? __htab_map_lookup_elem+0x4e/0x60
 ? bpf_prog_680e8aff8547aec1_kfree+0x3b/0x714
 ? trace_call_bpf+0xc8/0x150
 ? kfree+0x1/0x250
 ? kfree+0x1/0x250
 ? kprobe_perf_func+0x4f/0x2b0
 ? kprobe_perf_func+0x4f/0x2b0
 ? __mod_memcg_lruvec_state+0x63/0xe0
 netdev_port_receive+0xc4/0x180 [openvswitch]
 ? netdev_port_receive+0x180/0x180 [openvswitch]
 netdev_frame_hook+0x1f/0x40 [openvswitch]
 __netif_receive_skb_core.constprop.0+0x23d/0xf00
 __netif_receive_skb_one_core+0x3f/0xa0
 __netif_receive_skb+0x15/0x60
 process_backlog+0x9e/0x170
 __napi_poll+0x33/0x180
 net_rx_action+0x126/0x280
 ? ttwu_do_activate+0x72/0xf0
 __do_softirq+0xd9/0x2e7
 ? rcu_report_exp_cpu_mult+0x1b0/0x1b0
 do_softirq+0x7d/0xb0
 
 
 __local_bh_enable_ip+0x54/0x60
 ip_finish_output2+0x191/0x460
 __ip_finish_output+0xb7/0x180
 ip_finish_output+0x2e/0xc0
 ip_output+0x78/0x100
 ? __ip_finish_output+0x180/0x180
 ip_local_out+0x5e/0x70
 __ip_queue_xmit+0x184/0x440
 ? tcp_syn_options+0x1f9/0x300
 ip_queue_xmit+0x15/0x20
 __tcp_transmit_skb+0x910/0x9c0
 ? __mod_memcg_state+0x44/0xa0
 tcp_connect+0x437/0x4e0
 ? ktime_get_with_offset+0x60/0xf0
 tcp_v4_connect+0x436/0x530
 __inet_stream_connect+0xd4/0x3a0
 ? kprobe_perf_func+0x4f/0x2b0
 ? aa_sk_perm+0x43/0x1c0
 inet_stream_connect+0x3b/0x60
 __sys_connect_file+0x63/0x70
 __sys_connect+0xa6/0xd0
 ? setfl+0x108/0x170
 ? do_fcntl+0xe8/0x5a0
 __x64_sys_connect+0x18/0x20
 do_syscall_64+0x5c/0xc0
 ? __x64_sys_fcntl+0xa9/0xd0
 ? exit_to_user_mode_prepare+0x37/0xb0
 ? syscall_exit_to_user_mode+0x27/0x50
 ? do_syscall_64+0x69/0xc0
 ? __sys_setsockopt+0xea/0x1e0
 ? exit_to_user_mode_prepare+0x37/0xb0
 ? syscall_exit_to_user_mode+0x27/0x50
 ? __x64_sys_setsockopt+0x1f/0x30
 ? do_syscall_64+0x69/0xc0
 ? irqentry_exit+0x1d/0x30
 ? exc_page_fault+0x89/0x170
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f7b8101c6a7
Code: 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 18 89 54 24 0c 48 89 34 24 89
RSP: 002b:00007ffffd6b2198 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f7b8101c6a7
RDX: 0000000000000010 RSI: 00007ffffd6b2360 RDI: 0000000000000005
RBP: 0000561f1370d560 R08: 00002795ad21d1ac R09: 0030312e302e302e
R10: 00007ffffd73f080 R11: 0000000000000246 R12: 0000561f1370c410
R13: 0000000000000000 R14: 0000000000000005 R15: 0000000000000000
 

Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action")
Co-developed-by: Luca Czesla 
Signed-off-by: Luca Czesla 
Signed-off-by: Felix Huettner 
Reviewed-by: Eric Dumazet 
Reviewed-by: Simon Horman 
Link: https://lore.kernel.org/r/ZC0pBXBAgh7c76CA@kernel-bug-kernel-bug
Signed-off-by: Jakub Kicinski 
Signed-off-by: Carlos Soto 
Signed-off-by: Florian Fainelli 
Signed-off-by: Greg Kroah-Hartman