linux.git/net/openvswitch/conntrack.c, branch v4.13 Linux kernel source tree openvswitch: fix potential out of bound access in parse_ct 2017-07-24T23:25:06+00:00 Liping Zhang zlpnobody@gmail.com 2017-07-23T09:52:23+00:00 69ec932e364b1ba9c3a2085fe96b76c8a3f71e7c Before the 'type' is validated, we shouldn't use it to fetch the ovs_ct_attr_lens's minlen and maxlen, else, out of bound access may happen. Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action") Signed-off-by: Liping Zhang <zlpnobody@gmail.com> Acked-by: Pravin B Shelar <pshelar@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Before the 'type' is validated, we shouldn't use it to fetch the
ovs_ct_attr_lens's minlen and maxlen, else, out of bound access
may happen.

Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
openvswitch: Fix for force/commit action failures 2017-07-15T21:40:21+00:00 Greg Rose gvrose8192@gmail.com 2017-07-14T19:42:49+00:00 8b97ac5bda17cfaa257bcab6180af0f43a2e87e0 When there is an established connection in direction A->B, it is possible to receive a packet on port B which then executes ct(commit,force) without first performing ct() - ie, a lookup. In this case, we would expect that this packet can delete the existing entry so that we can commit a connection with direction B->A. However, currently we only perform a check in skb_nfct_cached() for whether OVS_CS_F_TRACKED is set and OVS_CS_F_INVALID is not set, ie that a lookup previously occurred. In the above scenario, a lookup has not occurred but we should still be able to statelessly look up the existing entry and potentially delete the entry if it is in the opposite direction. This patch extends the check to also hint that if the action has the force flag set, then we will lookup the existing entry so that the force check at the end of skb_nfct_cached has the ability to delete the connection. Fixes: dd41d330b03 ("openvswitch: Add force commit.") CC: Pravin Shelar <pshelar@nicira.com> CC: dev@openvswitch.org Signed-off-by: Joe Stringer <joe@ovn.org> Signed-off-by: Greg Rose <gvrose8192@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
When there is an established connection in direction A->B, it is
possible to receive a packet on port B which then executes
ct(commit,force) without first performing ct() - ie, a lookup.
In this case, we would expect that this packet can delete the existing
entry so that we can commit a connection with direction B->A. However,
currently we only perform a check in skb_nfct_cached() for whether
OVS_CS_F_TRACKED is set and OVS_CS_F_INVALID is not set, ie that a
lookup previously occurred. In the above scenario, a lookup has not
occurred but we should still be able to statelessly look up the
existing entry and potentially delete the entry if it is in the
opposite direction.

This patch extends the check to also hint that if the action has the
force flag set, then we will lookup the existing entry so that the
force check at the end of skb_nfct_cached has the ability to delete
the connection.

Fixes: dd41d330b03 ("openvswitch: Add force commit.")
CC: Pravin Shelar <pshelar@nicira.com>
CC: dev@openvswitch.org
Signed-off-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netfilter: introduce nf_conntrack_helper_put helper function 2017-05-15T10:42:29+00:00 Liping Zhang zlpnobody@gmail.com 2017-05-07T14:01:55+00:00 d91fc59cd77c719f33eda65c194ad8f95a055190 And convert module_put invocation to nf_conntrack_helper_put, this is prepared for the followup patch, which will add a refcnt for cthelper, so we can reject the deleting request when cthelper is in use. Signed-off-by: Liping Zhang <zlpnobody@gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
And convert module_put invocation to nf_conntrack_helper_put, this is
prepared for the followup patch, which will add a refcnt for cthelper,
so we can reject the deleting request when cthelper is in use.

Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2017-05-03T14:11:26+00:00 David S. Miller davem@davemloft.net 2017-05-03T14:11:26+00:00 4d89ac2dd559b343dad30a294fb11e0237d697d8 Pablo Neira Ayuso says: ==================== Netfilter/IPVS/OVS fixes for net The following patchset contains a rather large batch of Netfilter, IPVS and OVS fixes for your net tree. This includes fixes for ctnetlink, the userspace conntrack helper infrastructure, conntrack OVS support, ebtables DNAT target, several leaks in error path among other. More specifically, they are: 1) Fix reference count leak in the CT target error path, from Gao Feng. 2) Remove conntrack entry clashing with a matching expectation, patch from Jarno Rajahalme. 3) Fix bogus EEXIST when registering two different userspace helpers, from Liping Zhang. 4) Don't leak dummy elements in the new bitmap set type in nf_tables, from Liping Zhang. 5) Get rid of module autoload from conntrack update path in ctnetlink, we don't need autoload at this late stage and it is happening with rcu read lock held which is not good. From Liping Zhang. 6) Fix deadlock due to double-acquire of the expect_lock from conntrack update path, this fixes a bug that was introduced when the central spinlock got removed. Again from Liping Zhang. 7) Safe ct->status update from ctnetlink path, from Liping. The expect_lock protection that was selected when the central spinlock was removed was not really protecting anything at all. 8) Protect sequence adjustment under ct->lock. 9) Missing socket match with IPv6, from Peter Tirsek. 10) Adjust skb->pkt_type of DNAT'ed frames from ebtables, from Linus Luessing. 11) Don't give up on evaluating the expression on new entries added via dynset expression in nf_tables, from Liping Zhang. 12) Use skb_checksum() when mangling icmpv6 in IPv6 NAT as this deals with non-linear skbuffs. 13) Don't allow IPv6 service in IPVS if no IPv6 support is available, from Paolo Abeni. 14) Missing mutex release in error path of xt_find_table_lock(), from Dan Carpenter. 15) Update maintainers files, Netfilter section. Add Florian to the file, refer to nftables.org and change project status from Supported to Maintained. 16) Bail out on mismatching extensions in element updates in nf_tables. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> 
Pablo Neira Ayuso says:

====================
Netfilter/IPVS/OVS fixes for net

The following patchset contains a rather large batch of Netfilter, IPVS
and OVS fixes for your net tree. This includes fixes for ctnetlink, the
userspace conntrack helper infrastructure, conntrack OVS support,
ebtables DNAT target, several leaks in error path among other. More
specifically, they are:

1) Fix reference count leak in the CT target error path, from Gao Feng.

2) Remove conntrack entry clashing with a matching expectation, patch
   from Jarno Rajahalme.

3) Fix bogus EEXIST when registering two different userspace helpers,
   from Liping Zhang.

4) Don't leak dummy elements in the new bitmap set type in nf_tables,
   from Liping Zhang.

5) Get rid of module autoload from conntrack update path in ctnetlink,
   we don't need autoload at this late stage and it is happening with
   rcu read lock held which is not good. From Liping Zhang.

6) Fix deadlock due to double-acquire of the expect_lock from conntrack
   update path, this fixes a bug that was introduced when the central
   spinlock got removed. Again from Liping Zhang.

7) Safe ct->status update from ctnetlink path, from Liping. The expect_lock
   protection that was selected when the central spinlock was removed was
   not really protecting anything at all.

8) Protect sequence adjustment under ct->lock.

9) Missing socket match with IPv6, from Peter Tirsek.

10) Adjust skb->pkt_type of DNAT'ed frames from ebtables, from
    Linus Luessing.

11) Don't give up on evaluating the expression on new entries added via
    dynset expression in nf_tables, from Liping Zhang.

12) Use skb_checksum() when mangling icmpv6 in IPv6 NAT as this deals
    with non-linear skbuffs.

13) Don't allow IPv6 service in IPVS if no IPv6 support is available,
    from Paolo Abeni.

14) Missing mutex release in error path of xt_find_table_lock(), from
    Dan Carpenter.

15) Update maintainers files, Netfilter section. Add Florian to the
    file, refer to nftables.org and change project status from Supported
    to Maintained.

16) Bail out on mismatching extensions in element updates in nf_tables.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next 2017-05-01T14:47:53+00:00 David S. Miller davem@davemloft.net 2017-05-01T14:46:50+00:00 a01aa920b8e39069bb7ab352ce45f127238f1d26 Pablo Neira Ayuso says: ==================== Netfilter/IPVS updates for net-next The following patchset contains Netfilter updates for your net-next tree. A large bunch of code cleanups, simplify the conntrack extension codebase, get rid of the fake conntrack object, speed up netns by selective synchronize_net() calls. More specifically, they are: 1) Check for ct->status bit instead of using nfct_nat() from IPVS and Netfilter codebase, patch from Florian Westphal. 2) Use kcalloc() wherever possible in the IPVS code, from Varsha Rao. 3) Simplify FTP IPVS helper module registration path, from Arushi Singhal. 4) Introduce nft_is_base_chain() helper function. 5) Enforce expectation limit from userspace conntrack helper, from Gao Feng. 6) Add nf_ct_remove_expect() helper function, from Gao Feng. 7) NAT mangle helper function return boolean, from Gao Feng. 8) ctnetlink_alloc_expect() should only work for conntrack with helpers, from Gao Feng. 9) Add nfnl_msg_type() helper function to nfnetlink to build the netlink message type. 10) Get rid of unnecessary cast on void, from simran singhal. 11) Use seq_puts()/seq_putc() instead of seq_printf() where possible, also from simran singhal. 12) Use list_prev_entry() from nf_tables, from simran signhal. 13) Remove unnecessary & on pointer function in the Netfilter and IPVS code. 14) Remove obsolete comment on set of rules per CPU in ip6_tables, no longer true. From Arushi Singhal. 15) Remove duplicated nf_conntrack_l4proto_udplite4, from Gao Feng. 16) Remove unnecessary nested rcu_read_lock() in __nf_nat_decode_session(). Code running from hooks are already guaranteed to run under RCU read side. 17) Remove deadcode in nf_tables_getobj(), from Aaron Conole. 18) Remove double assignment in nf_ct_l4proto_pernet_unregister_one(), also from Aaron. 19) Get rid of unsed __ip_set_get_netlink(), from Aaron Conole. 20) Don't propagate NF_DROP error to userspace via ctnetlink in __nf_nat_alloc_null_binding() function, from Gao Feng. 21) Revisit nf_ct_deliver_cached_events() to remove unnecessary checks, from Gao Feng. 22) Kill the fake untracked conntrack objects, use ctinfo instead to annotate a conntrack object is untracked, from Florian Westphal. 23) Remove nf_ct_is_untracked(), now obsolete since we have no conntrack template anymore, from Florian. 24) Add event mask support to nft_ct, also from Florian. 25) Move nf_conn_help structure to include/net/netfilter/nf_conntrack_helper.h. 26) Add a fixed 32 bytes scratchpad area for conntrack helpers. Thus, we don't deal with variable conntrack extensions anymore. Make sure userspace conntrack helper doesn't go over that size. Remove variable size ct extension infrastructure now this code got no more clients. From Florian Westphal. 27) Restore offset and length of nf_ct_ext structure to 8 bytes now that wraparound is not possible any longer, also from Florian. 28) Allow to get rid of unassured flows under stress in conntrack, this applies to DCCP, SCTP and TCP protocols, from Florian. 29) Shrink size of nf_conntrack_ecache structure, from Florian. 30) Use TCP_MAX_WSCALE instead of hardcoded 14 in TCP tracker, from Gao Feng. 31) Register SYNPROXY hooks on demand, from Florian Westphal. 32) Use pernet hook whenever possible, instead of global hook registration, from Florian Westphal. 33) Pass hook structure to ebt_register_table() to consolidate some infrastructure code, from Florian Westphal. 34) Use consume_skb() and return NF_STOLEN, instead of NF_DROP in the SYNPROXY code, to make sure device stats are not fooled, patch from Gao Feng. 35) Remove NF_CT_EXT_F_PREALLOC this kills quite some code that we don't need anymore if we just select a fixed size instead of expensive runtime time calculation of this. From Florian. 36) Constify nf_ct_extend_register() and nf_ct_extend_unregister(), from Florian. 37) Simplify nf_ct_ext_add(), this kills nf_ct_ext_create(), from Florian. 38) Attach NAT extension on-demand from masquerade and pptp helper path, from Florian. 39) Get rid of useless ip_vs_set_state_timeout(), from Aaron Conole. 40) Speed up netns by selective calls of synchronize_net(), from Florian Westphal. 41) Silence stack size warning gcc in 32-bit arch in snmp helper, from Florian. 42) Inconditionally call nf_ct_ext_destroy(), even if we have no extensions, to deal with the NF_NAT_MANIP_SRC case. Patch from Liping Zhang. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> 
Pablo Neira Ayuso says:

====================
Netfilter/IPVS updates for net-next

The following patchset contains Netfilter updates for your net-next
tree. A large bunch of code cleanups, simplify the conntrack extension
codebase, get rid of the fake conntrack object, speed up netns by
selective synchronize_net() calls. More specifically, they are:

1) Check for ct->status bit instead of using nfct_nat() from IPVS and
   Netfilter codebase, patch from Florian Westphal.

2) Use kcalloc() wherever possible in the IPVS code, from Varsha Rao.

3) Simplify FTP IPVS helper module registration path, from Arushi Singhal.

4) Introduce nft_is_base_chain() helper function.

5) Enforce expectation limit from userspace conntrack helper,
   from Gao Feng.

6) Add nf_ct_remove_expect() helper function, from Gao Feng.

7) NAT mangle helper function return boolean, from Gao Feng.

8) ctnetlink_alloc_expect() should only work for conntrack with
   helpers, from Gao Feng.

9) Add nfnl_msg_type() helper function to nfnetlink to build the
   netlink message type.

10) Get rid of unnecessary cast on void, from simran singhal.

11) Use seq_puts()/seq_putc() instead of seq_printf() where possible,
    also from simran singhal.

12) Use list_prev_entry() from nf_tables, from simran signhal.

13) Remove unnecessary & on pointer function in the Netfilter and IPVS
    code.

14) Remove obsolete comment on set of rules per CPU in ip6_tables,
    no longer true. From Arushi Singhal.

15) Remove duplicated nf_conntrack_l4proto_udplite4, from Gao Feng.

16) Remove unnecessary nested rcu_read_lock() in
    __nf_nat_decode_session(). Code running from hooks are already
    guaranteed to run under RCU read side.

17) Remove deadcode in nf_tables_getobj(), from Aaron Conole.

18) Remove double assignment in nf_ct_l4proto_pernet_unregister_one(),
    also from Aaron.

19) Get rid of unsed __ip_set_get_netlink(), from Aaron Conole.

20) Don't propagate NF_DROP error to userspace via ctnetlink in
    __nf_nat_alloc_null_binding() function, from Gao Feng.

21) Revisit nf_ct_deliver_cached_events() to remove unnecessary checks,
    from Gao Feng.

22) Kill the fake untracked conntrack objects, use ctinfo instead to
    annotate a conntrack object is untracked, from Florian Westphal.

23) Remove nf_ct_is_untracked(), now obsolete since we have no
    conntrack template anymore, from Florian.

24) Add event mask support to nft_ct, also from Florian.

25) Move nf_conn_help structure to
    include/net/netfilter/nf_conntrack_helper.h.

26) Add a fixed 32 bytes scratchpad area for conntrack helpers.
    Thus, we don't deal with variable conntrack extensions anymore.
    Make sure userspace conntrack helper doesn't go over that size.
    Remove variable size ct extension infrastructure now this code
    got no more clients. From Florian Westphal.

27) Restore offset and length of nf_ct_ext structure to 8 bytes now
    that wraparound is not possible any longer, also from Florian.

28) Allow to get rid of unassured flows under stress in conntrack,
    this applies to DCCP, SCTP and TCP protocols, from Florian.

29) Shrink size of nf_conntrack_ecache structure, from Florian.

30) Use TCP_MAX_WSCALE instead of hardcoded 14 in TCP tracker,
    from Gao Feng.

31) Register SYNPROXY hooks on demand, from Florian Westphal.

32) Use pernet hook whenever possible, instead of global hook
    registration, from Florian Westphal.

33) Pass hook structure to ebt_register_table() to consolidate some
    infrastructure code, from Florian Westphal.

34) Use consume_skb() and return NF_STOLEN, instead of NF_DROP in the
    SYNPROXY code, to make sure device stats are not fooled, patch
    from Gao Feng.

35) Remove NF_CT_EXT_F_PREALLOC this kills quite some code that we
    don't need anymore if we just select a fixed size instead of
    expensive runtime time calculation of this. From Florian.

36) Constify nf_ct_extend_register() and nf_ct_extend_unregister(),
    from Florian.

37) Simplify nf_ct_ext_add(), this kills nf_ct_ext_create(), from
    Florian.

38) Attach NAT extension on-demand from masquerade and pptp helper
    path, from Florian.

39) Get rid of useless ip_vs_set_state_timeout(), from Aaron Conole.

40) Speed up netns by selective calls of synchronize_net(), from
    Florian Westphal.

41) Silence stack size warning gcc in 32-bit arch in snmp helper,
    from Florian.

42) Inconditionally call nf_ct_ext_destroy(), even if we have no
    extensions, to deal with the NF_NAT_MANIP_SRC case. Patch from
    Liping Zhang.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
openvswitch: Delete conntrack entry clashing with an expectation. 2017-04-24T18:04:41+00:00 Jarno Rajahalme jarno@ovn.org 2017-04-14T21:26:38+00:00 cf5d70918877c6a6655dc1e92e2ebb661ce904fd Conntrack helpers do not check for a potentially clashing conntrack entry when creating a new expectation. Also, nf_conntrack_in() will check expectations (via init_conntrack()) only if a conntrack entry can not be found. The expectation for a packet which also matches an existing conntrack entry will not be removed by conntrack, and is currently handled inconsistently by OVS, as OVS expects the expectation to be removed when the connection tracking entry matching that expectation is confirmed. It should be noted that normally an IP stack would not allow reuse of a 5-tuple of an old (possibly lingering) connection for a new data connection, so this is somewhat unlikely corner case. However, it is possible that a misbehaving source could cause conntrack entries be created that could then interfere with new related connections. Fix this in the OVS module by deleting the clashing conntrack entry after an expectation has been matched. This causes the following nf_conntrack_in() call also find the expectation and remove it when creating the new conntrack entry, as well as the forthcoming reply direction packets to match the new related connection instead of the old clashing conntrack entry. Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action") Reported-by: Yang Song <yangsong@vmware.com> Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
Conntrack helpers do not check for a potentially clashing conntrack
entry when creating a new expectation.  Also, nf_conntrack_in() will
check expectations (via init_conntrack()) only if a conntrack entry
can not be found.  The expectation for a packet which also matches an
existing conntrack entry will not be removed by conntrack, and is
currently handled inconsistently by OVS, as OVS expects the
expectation to be removed when the connection tracking entry matching
that expectation is confirmed.

It should be noted that normally an IP stack would not allow reuse of
a 5-tuple of an old (possibly lingering) connection for a new data
connection, so this is somewhat unlikely corner case.  However, it is
possible that a misbehaving source could cause conntrack entries be
created that could then interfere with new related connections.

Fix this in the OVS module by deleting the clashing conntrack entry
after an expectation has been matched.  This causes the following
nf_conntrack_in() call also find the expectation and remove it when
creating the new conntrack entry, as well as the forthcoming reply
direction packets to match the new related connection instead of the
old clashing conntrack entry.

Fixes: 7f8a436eaa2c ("openvswitch: Add conntrack action")
Reported-by: Yang Song <yangsong@vmware.com>
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
openvswitch: Add eventmask support to CT action. 2017-04-24T17:53:25+00:00 Jarno Rajahalme jarno@ovn.org 2017-04-21T23:48:06+00:00 120645513f55a4ac5543120d9e79925d30a0156f Add a new optional conntrack action attribute OVS_CT_ATTR_EVENTMASK, which can be used in conjunction with the commit flag (OVS_CT_ATTR_COMMIT) to set the mask of bits specifying which conntrack events (IPCT_*) should be delivered via the Netfilter netlink multicast groups. Default behavior depends on the system configuration, but typically a lot of events are delivered. This can be very chatty for the NFNLGRP_CONNTRACK_UPDATE group, even if only some types of events are of interest. Netfilter core init_conntrack() adds the event cache extension, so we only need to set the ctmask value. However, if the system is configured without support for events, the setting will be skipped due to extension not being found. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Reviewed-by: Greg Rose <gvrose8192@gmail.com> Acked-by: Joe Stringer <joe@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
Add a new optional conntrack action attribute OVS_CT_ATTR_EVENTMASK,
which can be used in conjunction with the commit flag
(OVS_CT_ATTR_COMMIT) to set the mask of bits specifying which
conntrack events (IPCT_*) should be delivered via the Netfilter
netlink multicast groups.  Default behavior depends on the system
configuration, but typically a lot of events are delivered.  This can be
very chatty for the NFNLGRP_CONNTRACK_UPDATE group, even if only some
types of events are of interest.

Netfilter core init_conntrack() adds the event cache extension, so we
only need to set the ctmask value.  However, if the system is
configured without support for events, the setting will be skipped due
to extension not being found.

Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Reviewed-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
openvswitch: Typo fix. 2017-04-24T17:53:24+00:00 Jarno Rajahalme jarno@ovn.org 2017-04-21T23:48:05+00:00 abd0a4f2b41812e9ba334945e256909e3d28da57 Fix typo in a comment. Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Greg Rose <gvrose8192@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Fix typo in a comment.

Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Greg Rose <gvrose8192@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netfilter: remove nf_ct_is_untracked 2017-04-15T09:51:33+00:00 Florian Westphal fw@strlen.de 2017-04-14T18:31:09+00:00 ab8bc7ed864b9c4f1fcb00a22bbe4e0f66ce8003 This function is now obsolete and always returns false. This change has no effect on generated code. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
This function is now obsolete and always returns false.
This change has no effect on generated code.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
openvswitch: Fix refcount leak on force commit. 2017-03-29T04:56:11+00:00 Jarno Rajahalme jarno@ovn.org 2017-03-28T18:25:26+00:00 b768b16de58d5e0b1d7c3f936825b25327ced20c The reference count held for skb needs to be released when the skb's nfct pointer is cleared regardless of if nf_ct_delete() is called or not. Failing to release the skb's reference cound led to deferred conntrack cleanup spinning forever within nf_conntrack_cleanup_net_list() when cleaning up a network namespace:    kworker/u16:0-19025 [004] 45981067.173642: sched_switch: kworker/u16:0:19025 [120] R ==> rcu_preempt:7 [120]    kworker/u16:0-19025 [004] 45981067.173651: kernel_stack: <stack trace> => ___preempt_schedule (ffffffffa001ed36) => _raw_spin_unlock_bh (ffffffffa0713290) => nf_ct_iterate_cleanup (ffffffffc00a4454) => nf_conntrack_cleanup_net_list (ffffffffc00a5e1e) => nf_conntrack_pernet_exit (ffffffffc00a63dd) => ops_exit_list.isra.1 (ffffffffa06075f3) => cleanup_net (ffffffffa0607df0) => process_one_work (ffffffffa0084c31) => worker_thread (ffffffffa008592b) => kthread (ffffffffa008bee2) => ret_from_fork (ffffffffa071b67c) Fixes: dd41d33f0b03 ("openvswitch: Add force commit.") Reported-by: Yang Song <yangsong@vmware.com> Signed-off-by: Jarno Rajahalme <jarno@ovn.org> Acked-by: Joe Stringer <joe@ovn.org> Signed-off-by: David S. Miller <davem@davemloft.net> 
The reference count held for skb needs to be released when the skb's
nfct pointer is cleared regardless of if nf_ct_delete() is called or
not.

Failing to release the skb's reference cound led to deferred conntrack
cleanup spinning forever within nf_conntrack_cleanup_net_list() when
cleaning up a network namespace:

   kworker/u16:0-19025 [004] 45981067.173642: sched_switch: kworker/u16:0:19025 [120] R ==> rcu_preempt:7 [120]
   kworker/u16:0-19025 [004] 45981067.173651: kernel_stack: <stack trace>
=> ___preempt_schedule (ffffffffa001ed36)
=> _raw_spin_unlock_bh (ffffffffa0713290)
=> nf_ct_iterate_cleanup (ffffffffc00a4454)
=> nf_conntrack_cleanup_net_list (ffffffffc00a5e1e)
=> nf_conntrack_pernet_exit (ffffffffc00a63dd)
=> ops_exit_list.isra.1 (ffffffffa06075f3)
=> cleanup_net (ffffffffa0607df0)
=> process_one_work (ffffffffa0084c31)
=> worker_thread (ffffffffa008592b)
=> kthread (ffffffffa008bee2)
=> ret_from_fork (ffffffffa071b67c)

Fixes: dd41d33f0b03 ("openvswitch: Add force commit.")
Reported-by: Yang Song <yangsong@vmware.com>
Signed-off-by: Jarno Rajahalme <jarno@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>