litmus-rt.git/net/bridge, branch master The LITMUS^RT kernel. bridge: fix br_stp_set_bridge_priority race conditions 2015-07-10T16:49:28+00:00 Nikolay Aleksandrov razor@blackwall.org 2015-06-15T17:28:51+00:00 08be544ef5d8453b7778bd57f3da8eeebcf1cd65 [ Upstream commit 2dab80a8b486f02222a69daca6859519e05781d9 ] After the ->set() spinlocks were removed br_stp_set_bridge_priority was left running without any protection when used via sysfs. It can race with port add/del and could result in use-after-free cases and corrupted lists. Tested by running port add/del in a loop with stp enabled while setting priority in a loop, crashes are easily reproducible. The spinlocks around sysfs ->set() were removed in commit: 14f98f258f19 ("bridge: range check STP parameters") There's also a race condition in the netlink priority support that is fixed by this change, but it was introduced recently and the fixes tag covers it, just in case it's needed the commit is: af615762e972 ("bridge: add ageing_time, stp_state, priority over netlink") Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org> Fixes: 14f98f258f19 ("bridge: range check STP parameters") Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 2dab80a8b486f02222a69daca6859519e05781d9 ]

After the ->set() spinlocks were removed br_stp_set_bridge_priority
was left running without any protection when used via sysfs. It can
race with port add/del and could result in use-after-free cases and
corrupted lists. Tested by running port add/del in a loop with stp
enabled while setting priority in a loop, crashes are easily
reproducible.
The spinlocks around sysfs ->set() were removed in commit:
14f98f258f19 ("bridge: range check STP parameters")
There's also a race condition in the netlink priority support that is
fixed by this change, but it was introduced recently and the fixes tag
covers it, just in case it's needed the commit is:
af615762e972 ("bridge: add ageing_time, stp_state, priority over netlink")

Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Fixes: 14f98f258f19 ("bridge: range check STP parameters")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
bridge: fix multicast router rlist endless loop 2015-06-11T05:07:50+00:00 Nikolay Aleksandrov razor@blackwall.org 2015-06-09T17:23:57+00:00 1a040eaca1a22f8da8285ceda6b5e4a2cb704867 Since the addition of sysfs multicast router support if one set multicast_router to "2" more than once, then the port would be added to the hlist every time and could end up linking to itself and thus causing an endless loop for rlist walkers. So to reproduce just do: echo 2 > multicast_router; echo 2 > multicast_router; in a bridge port and let some igmp traffic flow, for me it hangs up in br_multicast_flood(). Fix this by adding a check in br_multicast_add_router() if the port is already linked. The reason this didn't happen before the addition of multicast_router sysfs entries is because there's a !hlist_unhashed check that prevents it. Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org> Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries") Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net> 
Since the addition of sysfs multicast router support if one set
multicast_router to "2" more than once, then the port would be added to
the hlist every time and could end up linking to itself and thus causing an
endless loop for rlist walkers.
So to reproduce just do:
echo 2 > multicast_router; echo 2 > multicast_router;
in a bridge port and let some igmp traffic flow, for me it hangs up
in br_multicast_flood().
Fix this by adding a check in br_multicast_add_router() if the port is
already linked.
The reason this didn't happen before the addition of multicast_router
sysfs entries is because there's a !hlist_unhashed check that prevents
it.

Signed-off-by: Nikolay Aleksandrov <razor@blackwall.org>
Fixes: 0909e11758bd ("bridge: Add multicast_router sysfs entries")
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
bridge: disable softirqs around br_fdb_update to avoid lockup 2015-06-08T02:44:13+00:00 Nikolay Aleksandrov nikolay@cumulusnetworks.com 2015-06-06T13:49:00+00:00 c4c832f89dc468cf11dc0dd17206bace44526651 br_fdb_update() can be called in process context in the following way: br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set) so we need to disable softirqs because there are softirq users of the hash_lock. One easy way to reproduce this is to modify the bridge utility to set NTF_USE, enable stp and then set maxageing to a low value so br_fdb_cleanup() is called frequently and then just add new entries in a loop. This happens because br_fdb_cleanup() is called from timer/softirq context. The spin locks in br_fdb_update were _bh before commit f8ae737deea1 ("[BRIDGE]: forwarding remove unneeded preempt and bh diasables") and at the time that commit was correct because br_fdb_update() couldn't be called from process context, but that changed after commit: 292d1398983f ("bridge: add NTF_USE support") Using local_bh_disable/enable around br_fdb_update() allows us to keep using the spin_lock/unlock in br_fdb_update for the fast-path. Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Fixes: 292d1398983f ("bridge: add NTF_USE support") Signed-off-by: David S. Miller <davem@davemloft.net> 
br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to disable softirqs because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. The spin locks in br_fdb_update were _bh before commit f8ae737deea1
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398983f ("bridge: add NTF_USE support")
Using local_bh_disable/enable around br_fdb_update() allows us to keep
using the spin_lock/unlock in br_fdb_update for the fast-path.

Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: David S. Miller <davem@davemloft.net>
Revert "bridge: use _bh spinlock variant for br_fdb_update to avoid lockup" 2015-06-08T02:43:47+00:00 David S. Miller davem@davemloft.net 2015-06-08T02:43:47+00:00 7ff46e79fb7df5b09c46c36857929fdf039f8b31 This reverts commit 1d7c49037b12016e7056b9f2c990380e2187e766. Nikolay Aleksandrov has a better version of this fix. Signed-off-by: David S. Miller <davem@davemloft.net> 
This reverts commit 1d7c49037b12016e7056b9f2c990380e2187e766.

Nikolay Aleksandrov has a better version of this fix.

Signed-off-by: David S. Miller <davem@davemloft.net>
bridge: use _bh spinlock variant for br_fdb_update to avoid lockup 2015-06-07T22:24:54+00:00 Wilson Kok wkok@cumulusnetworks.com 2015-06-05T07:52:57+00:00 1d7c49037b12016e7056b9f2c990380e2187e766 br_fdb_update() can be called in process context in the following way: br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set) so we need to use spin_lock_bh because there are softirq users of the hash_lock. One easy way to reproduce this is to modify the bridge utility to set NTF_USE, enable stp and then set maxageing to a low value so br_fdb_cleanup() is called frequently and then just add new entries in a loop. This happens because br_fdb_cleanup() is called from timer/softirq context. These locks were _bh before commit f8ae737deea1 ("[BRIDGE]: forwarding remove unneeded preempt and bh diasables") and at the time that commit was correct because br_fdb_update() couldn't be called from process context, but that changed after commit: 292d1398983f ("bridge: add NTF_USE support") Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Fixes: 292d1398983f ("bridge: add NTF_USE support") Signed-off-by: David S. Miller <davem@davemloft.net> 
br_fdb_update() can be called in process context in the following way:
br_fdb_add() -> __br_fdb_add() -> br_fdb_update() (if NTF_USE flag is set)
so we need to use spin_lock_bh because there are softirq users of the
hash_lock. One easy way to reproduce this is to modify the bridge utility
to set NTF_USE, enable stp and then set maxageing to a low value so
br_fdb_cleanup() is called frequently and then just add new entries in
a loop. This happens because br_fdb_cleanup() is called from timer/softirq
context. These locks were _bh before commit f8ae737deea1
("[BRIDGE]: forwarding remove unneeded preempt and bh diasables")
and at the time that commit was correct because br_fdb_update() couldn't be
called from process context, but that changed after commit:
292d1398983f ("bridge: add NTF_USE support")

Signed-off-by: Wilson Kok <wkok@cumulusnetworks.com>
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Fixes: 292d1398983f ("bridge: add NTF_USE support")
Signed-off-by: David S. Miller <davem@davemloft.net>
Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2015-06-01T23:56:43+00:00 David S. Miller davem@davemloft.net 2015-06-01T23:56:43+00:00 e453581dd518f60b45a8d2b9cf344e2a87d5267e Pablo Neira Ayuso says: ==================== Netfilter fix for net The following patch reverts the ebtables chunk that enforces counters that was introduced in the recently applied d26e2c9ffa38 ('Revert "netfilter: ensure number of counters is >0 in do_replace()"') since this breaks ebtables. ==================== Signed-off-by: David S. Miller <davem@davemloft.net> 
Pablo Neira Ayuso says:

====================
Netfilter fix for net

The following patch reverts the ebtables chunk that enforces counters that was
introduced in the recently applied d26e2c9ffa38 ('Revert "netfilter: ensure
number of counters is >0 in do_replace()"') since this breaks ebtables.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
Revert "netfilter: ensure number of counters is >0 in do_replace()" 2015-06-01T17:45:47+00:00 Bernhard Thaler bernhard.thaler@wvnet.at 2015-05-28T08:26:18+00:00 d26e2c9ffa385dd1b646f43c1397ba12af9ed431 This partially reverts commit 1086bbe97a07 ("netfilter: ensure number of counters is >0 in do_replace()") in net/bridge/netfilter/ebtables.c. Setting rules with ebtables does not work any more with 1086bbe97a07 place. There is an error message and no rules set in the end. e.g. ~# ebtables -t nat -A POSTROUTING --src 12:34:56:78:9a:bc -j DROP Unable to update the kernel. Two possible causes: 1. Multiple ebtables programs were executing simultaneously. The ebtables userspace tool doesn't by default support multiple ebtables programs running Reverting the ebtables part of 1086bbe97a07 makes this work again. Signed-off-by: Bernhard Thaler <bernhard.thaler@wvnet.at> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> 
This partially reverts commit 1086bbe97a07 ("netfilter: ensure number of
counters is >0 in do_replace()") in net/bridge/netfilter/ebtables.c.

Setting rules with ebtables does not work any more with 1086bbe97a07 place.

There is an error message and no rules set in the end.

e.g.

~# ebtables -t nat -A POSTROUTING --src 12:34:56:78:9a:bc -j DROP
Unable to update the kernel. Two possible causes:
1. Multiple ebtables programs were executing simultaneously. The ebtables
   userspace tool doesn't by default support multiple ebtables programs
running

Reverting the ebtables part of 1086bbe97a07 makes this work again.

Signed-off-by: Bernhard Thaler <bernhard.thaler@wvnet.at>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
bridge: fix br_multicast_query_expired() bug 2015-05-31T06:31:28+00:00 Eric Dumazet edumazet@google.com 2015-05-28T11:42:54+00:00 71d9f6149cac8fc6646adfb2a6f3b0de6ddd23f6 br_multicast_query_expired() querier argument is a pointer to a struct bridge_mcast_querier : struct bridge_mcast_querier { struct br_ip addr; struct net_bridge_port __rcu *port; }; Intent of the code was to clear port field, not the pointer to querier. Fixes: 2cd4143192e8 ("bridge: memorize and export selected IGMP/MLD querier port") Signed-off-by: Eric Dumazet <edumazet@google.com> Acked-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com> Acked-by: Linus Lüssing <linus.luessing@c0d3.blue> Cc: Linus Lüssing <linus.luessing@web.de> Cc: Steinar H. Gunderson <sesse@samfundet.no> Signed-off-by: David S. Miller <davem@davemloft.net> 
br_multicast_query_expired() querier argument is a pointer to
a struct bridge_mcast_querier :

struct bridge_mcast_querier {
        struct br_ip addr;
        struct net_bridge_port __rcu    *port;
};

Intent of the code was to clear port field, not the pointer to querier.

Fixes: 2cd4143192e8 ("bridge: memorize and export selected IGMP/MLD querier port")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Acked-by: Linus Lüssing <linus.luessing@c0d3.blue>
Cc: Linus Lüssing <linus.luessing@web.de>
Cc: Steinar H. Gunderson <sesse@samfundet.no>
Signed-off-by: David S. Miller <davem@davemloft.net>
bridge: fix lockdep splat 2015-05-22T20:23:56+00:00 Eric Dumazet edumazet@google.com 2015-05-21T20:28:29+00:00 93a33a584e2a49a217118148125944fd02d47b54 Following lockdep splat was reported : [ 29.382286] =============================== [ 29.382315] [ INFO: suspicious RCU usage. ] [ 29.382344] 4.1.0-0.rc0.git11.1.fc23.x86_64 #1 Not tainted [ 29.382380] ------------------------------- [ 29.382409] net/bridge/br_private.h:626 suspicious rcu_dereference_check() usage! [ 29.382455] other info that might help us debug this: [ 29.382507] rcu_scheduler_active = 1, debug_locks = 0 [ 29.382549] 2 locks held by swapper/0/0: [ 29.382576] #0: (((&p->forward_delay_timer))){+.-...}, at: [<ffffffff81139f75>] call_timer_fn+0x5/0x4f0 [ 29.382660] #1: (&(&br->lock)->rlock){+.-...}, at: [<ffffffffa0450dc1>] br_forward_delay_timer_expired+0x31/0x140 [bridge] [ 29.382754] stack backtrace: [ 29.382787] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.1.0-0.rc0.git11.1.fc23.x86_64 #1 [ 29.382838] Hardware name: LENOVO 422916G/LENOVO, BIOS A1KT53AUS 04/07/2015 [ 29.382882] 0000000000000000 3ebfc20364115825 ffff880666603c48 ffffffff81892d4b [ 29.382943] 0000000000000000 ffffffff81e124e0 ffff880666603c78 ffffffff8110bcd7 [ 29.383004] ffff8800785c9d00 ffff88065485ac58 ffff880c62002800 ffff880c5fc88ac0 [ 29.383065] Call Trace: [ 29.383084] <IRQ> [<ffffffff81892d4b>] dump_stack+0x4c/0x65 [ 29.383130] [<ffffffff8110bcd7>] lockdep_rcu_suspicious+0xe7/0x120 [ 29.383178] [<ffffffffa04520f9>] br_fill_ifinfo+0x4a9/0x6a0 [bridge] [ 29.383225] [<ffffffffa045266b>] br_ifinfo_notify+0x11b/0x4b0 [bridge] [ 29.383271] [<ffffffffa0450d90>] ? br_hold_timer_expired+0x70/0x70 [bridge] [ 29.383320] [<ffffffffa0450de8>] br_forward_delay_timer_expired+0x58/0x140 [bridge] [ 29.383371] [<ffffffffa0450d90>] ? br_hold_timer_expired+0x70/0x70 [bridge] [ 29.383416] [<ffffffff8113a033>] call_timer_fn+0xc3/0x4f0 [ 29.383454] [<ffffffff81139f75>] ? call_timer_fn+0x5/0x4f0 [ 29.383493] [<ffffffff8110a90f>] ? lock_release_holdtime.part.29+0xf/0x200 [ 29.383541] [<ffffffffa0450d90>] ? br_hold_timer_expired+0x70/0x70 [bridge] [ 29.383587] [<ffffffff8113a6a4>] run_timer_softirq+0x244/0x490 [ 29.383629] [<ffffffff810b68cc>] __do_softirq+0xec/0x670 [ 29.383666] [<ffffffff810b70d5>] irq_exit+0x145/0x150 [ 29.383703] [<ffffffff8189f506>] smp_apic_timer_interrupt+0x46/0x60 [ 29.383744] [<ffffffff8189d523>] apic_timer_interrupt+0x73/0x80 [ 29.383782] <EOI> [<ffffffff816f131f>] ? cpuidle_enter_state+0x5f/0x2f0 [ 29.383832] [<ffffffff816f131b>] ? cpuidle_enter_state+0x5b/0x2f0 Problem here is that br_forward_delay_timer_expired() is a timer handler, calling br_ifinfo_notify() which assumes either rcu_read_lock() or RTNL are held. Simplest fix seems to add rcu read lock section. Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Josh Boyer <jwboyer@fedoraproject.org> Reported-by: Dominick Grift <dac.override@gmail.com> Cc: Vlad Yasevich <vyasevich@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> 
Following lockdep splat was reported :

[   29.382286] ===============================
[   29.382315] [ INFO: suspicious RCU usage. ]
[   29.382344] 4.1.0-0.rc0.git11.1.fc23.x86_64 #1 Not tainted
[   29.382380] -------------------------------
[   29.382409] net/bridge/br_private.h:626 suspicious
rcu_dereference_check() usage!
[   29.382455]
               other info that might help us debug this:

[   29.382507]
               rcu_scheduler_active = 1, debug_locks = 0
[   29.382549] 2 locks held by swapper/0/0:
[   29.382576]  #0:  (((&p->forward_delay_timer))){+.-...}, at:
[<ffffffff81139f75>] call_timer_fn+0x5/0x4f0
[   29.382660]  #1:  (&(&br->lock)->rlock){+.-...}, at:
[<ffffffffa0450dc1>] br_forward_delay_timer_expired+0x31/0x140
[bridge]
[   29.382754]
               stack backtrace:
[   29.382787] CPU: 0 PID: 0 Comm: swapper/0 Not tainted
4.1.0-0.rc0.git11.1.fc23.x86_64 #1
[   29.382838] Hardware name: LENOVO 422916G/LENOVO, BIOS A1KT53AUS 04/07/2015
[   29.382882]  0000000000000000 3ebfc20364115825 ffff880666603c48
ffffffff81892d4b
[   29.382943]  0000000000000000 ffffffff81e124e0 ffff880666603c78
ffffffff8110bcd7
[   29.383004]  ffff8800785c9d00 ffff88065485ac58 ffff880c62002800
ffff880c5fc88ac0
[   29.383065] Call Trace:
[   29.383084]  <IRQ>  [<ffffffff81892d4b>] dump_stack+0x4c/0x65
[   29.383130]  [<ffffffff8110bcd7>] lockdep_rcu_suspicious+0xe7/0x120
[   29.383178]  [<ffffffffa04520f9>] br_fill_ifinfo+0x4a9/0x6a0 [bridge]
[   29.383225]  [<ffffffffa045266b>] br_ifinfo_notify+0x11b/0x4b0 [bridge]
[   29.383271]  [<ffffffffa0450d90>] ? br_hold_timer_expired+0x70/0x70 [bridge]
[   29.383320]  [<ffffffffa0450de8>]
br_forward_delay_timer_expired+0x58/0x140 [bridge]
[   29.383371]  [<ffffffffa0450d90>] ? br_hold_timer_expired+0x70/0x70 [bridge]
[   29.383416]  [<ffffffff8113a033>] call_timer_fn+0xc3/0x4f0
[   29.383454]  [<ffffffff81139f75>] ? call_timer_fn+0x5/0x4f0
[   29.383493]  [<ffffffff8110a90f>] ? lock_release_holdtime.part.29+0xf/0x200
[   29.383541]  [<ffffffffa0450d90>] ? br_hold_timer_expired+0x70/0x70 [bridge]
[   29.383587]  [<ffffffff8113a6a4>] run_timer_softirq+0x244/0x490
[   29.383629]  [<ffffffff810b68cc>] __do_softirq+0xec/0x670
[   29.383666]  [<ffffffff810b70d5>] irq_exit+0x145/0x150
[   29.383703]  [<ffffffff8189f506>] smp_apic_timer_interrupt+0x46/0x60
[   29.383744]  [<ffffffff8189d523>] apic_timer_interrupt+0x73/0x80
[   29.383782]  <EOI>  [<ffffffff816f131f>] ? cpuidle_enter_state+0x5f/0x2f0
[   29.383832]  [<ffffffff816f131b>] ? cpuidle_enter_state+0x5b/0x2f0

Problem here is that br_forward_delay_timer_expired() is a timer
handler, calling br_ifinfo_notify() which assumes either rcu_read_lock()
or RTNL are held.

Simplest fix seems to add rcu read lock section.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Josh Boyer <jwboyer@fedoraproject.org>
Reported-by: Dominick Grift <dac.override@gmail.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
bridge: fix parsing of MLDv2 reports 2015-05-22T19:08:20+00:00 Thadeu Lima de Souza Cascardo cascardo@redhat.com 2015-05-22T15:18:59+00:00 47cc84ce0c2fe75c99ea5963c4b5704dd78ead54 When more than a multicast address is present in a MLDv2 report, all but the first address is ignored, because the code breaks out of the loop if there has not been an error adding that address. This has caused failures when two guests connected through the bridge tried to communicate using IPv6. Neighbor discoveries would not be transmitted to the other guest when both used a link-local address and a static address. This only happens when there is a MLDv2 querier in the network. The fix will only break out of the loop when there is a failure adding a multicast address. The mdb before the patch: dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp dev ovirtmgmt port bond0.86 grp ff02::2 temp After the patch: dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp dev ovirtmgmt port bond0.86 grp ff02::fb temp dev ovirtmgmt port bond0.86 grp ff02::2 temp dev ovirtmgmt port bond0.86 grp ff02::d temp dev ovirtmgmt port vnet0 grp ff02::1:ff00:76 temp dev ovirtmgmt port bond0.86 grp ff02::16 temp dev ovirtmgmt port vnet1 grp ff02::1:ff00:77 temp dev ovirtmgmt port bond0.86 grp ff02::1:ff00:def temp dev ovirtmgmt port bond0.86 grp ff02::1:ffa1:40bf temp Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.") Reported-by: Rik Theys <Rik.Theys@esat.kuleuven.be> Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com> Tested-by: Rik Theys <Rik.Theys@esat.kuleuven.be> Signed-off-by: David S. Miller <davem@davemloft.net> 
When more than a multicast address is present in a MLDv2 report, all but
the first address is ignored, because the code breaks out of the loop if
there has not been an error adding that address.

This has caused failures when two guests connected through the bridge
tried to communicate using IPv6. Neighbor discoveries would not be
transmitted to the other guest when both used a link-local address and a
static address.

This only happens when there is a MLDv2 querier in the network.

The fix will only break out of the loop when there is a failure adding a
multicast address.

The mdb before the patch:

dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp

After the patch:

dev ovirtmgmt port vnet0 grp ff02::1:ff7d:6603 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff7d:6604 temp
dev ovirtmgmt port bond0.86 grp ff02::fb temp
dev ovirtmgmt port bond0.86 grp ff02::2 temp
dev ovirtmgmt port bond0.86 grp ff02::d temp
dev ovirtmgmt port vnet0 grp ff02::1:ff00:76 temp
dev ovirtmgmt port bond0.86 grp ff02::16 temp
dev ovirtmgmt port vnet1 grp ff02::1:ff00:77 temp
dev ovirtmgmt port bond0.86 grp ff02::1:ff00:def temp
dev ovirtmgmt port bond0.86 grp ff02::1:ffa1:40bf temp

Fixes: 08b202b67264 ("bridge br_multicast: IPv6 MLD support.")
Reported-by: Rik Theys <Rik.Theys@esat.kuleuven.be>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@redhat.com>
Tested-by: Rik Theys <Rik.Theys@esat.kuleuven.be>
Signed-off-by: David S. Miller <davem@davemloft.net>