[3.16.y-ckt stable] Patch "bonding: fix panic on non-ARPHRD_ETHER enslave failure" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    bonding: fix panic on non-ARPHRD_ETHER enslave failure

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt21.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From e99c96f3d6d8d8ff890dd0306d6519c393ddb164 Mon Sep 17 00:00:00 2001
From: Jay Vosburgh <jay.vosburgh at canonical.com>
Date: Fri, 6 Nov 2015 17:23:23 -0800
Subject: bonding: fix panic on non-ARPHRD_ETHER enslave failure

commit 40baec225765c54eefa870530dd613bad9829bb7 upstream.

Since commit 7d5cd2ce529b, when bond_enslave fails on devices that
are not ARPHRD_ETHER, if needed, it resets the bonding device back to
ARPHRD_ETHER by calling ether_setup.

	Unfortunately, ether_setup clobbers dev->flags, clearing IFF_UP
if the bond device is up, leaving it in a quasi-down state without
having actually gone through dev_close.  For bonding, if any periodic
work queue items are active (miimon, arp_interval, etc), those will
remain running, as they are stopped by bond_close.  At this point, if
the bonding module is unloaded or the bond is deleted, the system will
panic when the work function is called.

	This panic is resolved by calling dev_close on the bond itself
prior to calling ether_setup.

Cc: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
Signed-off-by: Jay Vosburgh <jay.vosburgh at canonical.com>
Fixes: 7d5cd2ce5292 ("bonding: correctly handle bonding type change on enslave failure")
Acked-by: Nikolay Aleksandrov <nikolay at cumulusnetworks.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/net/bonding/bond_main.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index ddb2e2564470..8fe94f711f39 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1667,6 +1667,7 @@ err_undo_flags:
 					    slave_dev->dev_addr))
 			eth_hw_addr_random(bond_dev);
 		if (bond_dev->type != ARPHRD_ETHER) {
+			dev_close(bond_dev);
 			ether_setup(bond_dev);
 			bond_dev->flags |= IFF_MASTER;
 			bond_dev->priv_flags &= ~IFF_TX_SKB_SHARING;