[PATCH 3.12 04/83] bonding: RCUify bond_set_rx_mode()

Greg Kroah-Hartman
2013-12-06T22:44:10Z

From: Veaceslav Falico <vfalico@redhat.com>

[ Upstream commit b32418705107265dfca5edfe2b547643e53a732e ]

Currently we rely on rtnl locking in bond_set_rx_mode(), however it's not
always the case:

RTNL: assertion failed at drivers/net/bonding/bond_main.c (3391)
...
[<ffffffff81651ca5>] dump_stack+0x54/0x74
[<ffffffffa029e717>] bond_set_rx_mode+0xc7/0xd0 [bonding]
[<ffffffff81553af7>] __dev_set_rx_mode+0x57/0xa0
[<ffffffff81557ff8>] __dev_mc_add+0x58/0x70
[<ffffffff81558020>] dev_mc_add+0x10/0x20
[<ffffffff8161e26e>] igmp6_group_added+0x18e/0x1d0
[<ffffffff81186f76>] ? kmem_cache_alloc_trace+0x236/0x260
[<ffffffff8161f80f>] ipv6_dev_mc_inc+0x29f/0x320
[<ffffffff8161f9e7>] ipv6_sock_mc_join+0x157/0x260
...

Fix this by using RCU primitives.

Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Tested-by: Joe Lawrence <joe.lawrence@stratus.com>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/bonding/bond_main.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -3395,20 +3395,20 @@ static void bond_set_rx_mode(struct net_
struct bonding *bond = netdev_priv(bond_dev);
struct slave *slave;

- ASSERT_RTNL();
-
+ rcu_read_lock();
if (USES_PRIMARY(bond->params.mode)) {
- slave = rtnl_dereference(bond->curr_active_slave);
+ slave = rcu_dereference(bond->curr_active_slave);
if (slave) {
dev_uc_sync(slave->dev, bond_dev);
dev_mc_sync(slave->dev, bond_dev);
}
} else {
- bond_for_each_slave(bond, slave) {
+ bond_for_each_slave_rcu(bond, slave) {
dev_uc_sync_multiple(slave->dev, bond_dev);
dev_mc_sync_multiple(slave->dev, bond_dev);
}
}
+ rcu_read_unlock();
}

static int bond_neigh_init(struct neighbour *n)