| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.1 142/159] bridge: netlink: fix slave_changelink/br_setport race conditions | Date | Sat, 26 Sep 2015 13:56:28 -0700 |
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4.1-stable review patch. If anyone has any objections, please let me know.
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From: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
[ Upstream commit 963ad94853000ab100f5ff19eea80095660d41b4 ]
Since slave_changelink support was added there have been a few race conditions when using br_setport() since some of the port functions it uses require the bridge lock. It is very easy to trigger a lockup due to some internal spin_lock() usage without bh disabled, also it's possible to get the bridge into an inconsistent state.
Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com> Fixes: 3ac636b8591c ("bridge: implement rtnl_link_ops->slave_changelink") Reviewed-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/bridge/br_netlink.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
--- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -711,9 +711,17 @@ static int br_port_slave_changelink(stru struct nlattr *tb[], struct nlattr *data[]) { + struct net_bridge *br = netdev_priv(brdev); + int ret; + if (!data) return 0; - return br_setport(br_port_get_rtnl(dev), data); + + spin_lock_bh(&br->lock); + ret = br_setport(br_port_get_rtnl(dev), data); + spin_unlock_bh(&br->lock); + + return ret; } static int br_port_fill_slave_info(struct sk_buff *skb,
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