This is a note to let you know that I've just added the patch titled

net: bridge: fix early call to br_stp_change_bridge_id and plug newlink leaks

to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: net-bridge-fix-early-call-to-br_stp_change_bridge_id-and-plug-newlink-leaks.patch and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Sun Dec 31 11:20:35 CET 2017

From: Nikolay Aleksandrov nikolay@cumulusnetworks.com Date: Mon, 18 Dec 2017 17:35:09 +0200 Subject: net: bridge: fix early call to br_stp_change_bridge_id and plug newlink leaks

From: Nikolay Aleksandrov nikolay@cumulusnetworks.com

[ Upstream commit 84aeb437ab98a2bce3d4b2111c79723aedfceb33 ]

The early call to br_stp_change_bridge_id in bridge's newlink can cause a memory leak if an error occurs during the newlink because the fdb entries are not cleaned up if a different lladdr was specified, also another minor issue is that it generates fdb notifications with ifindex = 0. Another unrelated memory leak is the bridge sysfs entries which get added on NETDEV_REGISTER event, but are not cleaned up in the newlink error path. To remove this special case the call to br_stp_change_bridge_id is done after netdev register and we cleanup the bridge on changelink error via br_dev_delete to plug all leaks.

This patch makes netlink bridge destruction on newlink error the same as dellink and ioctl del which is necessary since at that point we have a fully initialized bridge device.

To reproduce the issue: $ ip l add br0 address 00:11:22:33:44:55 type bridge group_fwd_mask 1 RTNETLINK answers: Invalid argument

$ rmmod bridge [ 1822.142525] ============================================================================= [ 1822.143640] BUG bridge_fdb_cache (Tainted: G O ): Objects remaining in bridge_fdb_cache on __kmem_cache_shutdown() [ 1822.144821] -----------------------------------------------------------------------------

[ 1822.145990] Disabling lock debugging due to kernel taint [ 1822.146732] INFO: Slab 0x0000000092a844b2 objects=32 used=2 fp=0x00000000fef011b0 flags=0x1ffff8000000100 [ 1822.147700] CPU: 2 PID: 13584 Comm: rmmod Tainted: G B O 4.15.0-rc2+ #87 [ 1822.148578] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014 [ 1822.150008] Call Trace: [ 1822.150510] dump_stack+0x78/0xa9 [ 1822.151156] slab_err+0xb1/0xd3 [ 1822.151834] ? __kmalloc+0x1bb/0x1ce [ 1822.152546] __kmem_cache_shutdown+0x151/0x28b [ 1822.153395] shutdown_cache+0x13/0x144 [ 1822.154126] kmem_cache_destroy+0x1c0/0x1fb [ 1822.154669] SyS_delete_module+0x194/0x244 [ 1822.155199] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 1822.155773] entry_SYSCALL_64_fastpath+0x23/0x9a [ 1822.156343] RIP: 0033:0x7f929bd38b17 [ 1822.156859] RSP: 002b:00007ffd160e9a98 EFLAGS: 00000202 ORIG_RAX: 00000000000000b0 [ 1822.157728] RAX: ffffffffffffffda RBX: 00005578316ba090 RCX: 00007f929bd38b17 [ 1822.158422] RDX: 00007f929bd9ec60 RSI: 0000000000000800 RDI: 00005578316ba0f0 [ 1822.159114] RBP: 0000000000000003 R08: 00007f929bff5f20 R09: 00007ffd160e8a11 [ 1822.159808] R10: 00007ffd160e9860 R11: 0000000000000202 R12: 00007ffd160e8a80 [ 1822.160513] R13: 0000000000000000 R14: 0000000000000000 R15: 00005578316ba090 [ 1822.161278] INFO: Object 0x000000007645de29 @offset=0 [ 1822.161666] INFO: Object 0x00000000d5df2ab5 @offset=128

Fixes: 30313a3d5794 ("bridge: Handle IFLA_ADDRESS correctly when creating bridge device") Fixes: 5b8d5429daa0 ("bridge: netlink: register netdevice before executing changelink") Signed-off-by: Nikolay Aleksandrov nikolay@cumulusnetworks.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/bridge/br_netlink.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/net/bridge/br_netlink.c +++ b/net/bridge/br_netlink.c @@ -1067,19 +1067,20 @@ static int br_dev_newlink(struct net *sr struct net_bridge *br = netdev_priv(dev); int err;

+ err = register_netdevice(dev); + if (err) + return err; + if (tb[IFLA_ADDRESS]) { spin_lock_bh(&br->lock); br_stp_change_bridge_id(br, nla_data(tb[IFLA_ADDRESS])); spin_unlock_bh(&br->lock); }

- err = register_netdevice(dev); - if (err) - return err; - err = br_changelink(dev, tb, data); if (err) - unregister_netdevice(dev); + br_dev_delete(dev, NULL); + return err; }

Patches currently in stable-queue which might be from nikolay@cumulusnetworks.com are

queue-4.4/net-bridge-fix-early-call-to-br_stp_change_bridge_id-and-plug-newlink-leaks.patch