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Date: Mon, 24 Apr 2017 15:25:30 +0800 From: Xin Long <lucien.xin@...il.com> To: network dev <netdev@...r.kernel.org> Cc: davem@...emloft.net, nikolay@...ulusnetworks.com Subject: [PATCH net] bridge: shutdown bridge device before removing it During removing a bridge device, if the bridge is still up, a new mdb entry still can be added in br_multicast_add_group() after all mdb entries are removed in br_multicast_dev_del(). Like the path: mld_ifc_timer_expire -> mld_sendpack -> ... br_multicast_rcv -> br_multicast_add_group The new mp's timer will be set up. If the timer expires after the bridge is freed, it may cause use-after-free panic in br_multicast_group_expired. This can happen when ip link remove a bridge or destroy a netns with a bridge device inside. As we can see in br_del_bridge, brctl is also supposed to remove a bridge device after it's shutdown. This patch is to call dev_close at the beginning of br_dev_delete so that netif_running check in br_multicast_add_group can avoid this issue. But to keep consistent with before, it will not remove the IFF_UP check in br_del_bridge for brctl. Reported-by: Jianwen Ji <jiji@...hat.com> Signed-off-by: Xin Long <lucien.xin@...il.com> --- net/bridge/br_if.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/bridge/br_if.c b/net/bridge/br_if.c index 56a2a72..8175f13 100644 --- a/net/bridge/br_if.c +++ b/net/bridge/br_if.c @@ -305,6 +305,8 @@ void br_dev_delete(struct net_device *dev, struct list_head *head) struct net_bridge *br = netdev_priv(dev); struct net_bridge_port *p, *n; + dev_close(br->dev); + list_for_each_entry_safe(p, n, &br->port_list, list) { del_nbp(p); } -- 2.1.0
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