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Patch "IB/ipoib: rtnl_unlock can not come after free_netdev" has been added to the 4.9-stable tree

PATCH [email protected] 1 participant 1 message Oct 5, 2017

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

IB/ipoib: rtnl_unlock can not come after free_netdev

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
ib-ipoib-rtnl_unlock-can-not-come-after-free_netdev.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Thu Oct 5 10:28:31 CEST 2017

From: Feras Daoud <[email protected]>
Date: Wed, 28 Dec 2016 14:47:24 +0200
Subject: IB/ipoib: rtnl_unlock can not come after free_netdev

From: Feras Daoud <[email protected]>

[ Upstream commit 89a3987ab7a923c047c6dec008e60ad6f41fac22 ]

The ipoib_vlan_add function calls rtnl_unlock after free_netdev, rtnl_unlock not only releases the lock, but also calls netdev_run_todo. The latter function browses the net_todo_list array and completes the unregistration of all its net_device instances. If we call free_netdev before rtnl_unlock, then netdev_run_todo call over the freed device causes panic.
To fix, move rtnl_unlock call before free_netdev call.

Fixes 9baa0b036410 ("IB/ipoib: Add rtnl_link_ops support")
Cc Or Gerlitz <[email protected]>
---
 drivers/infiniband/ulp/ipoib/ipoib_vlan.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
drivers/infiniband/ulp/ipoib/ipoib_vlan.c +2 -2
@@ -165,11 +165,11 @@ int ipoib_vlan_add(struct net_device *pd
 out:
 	up_write(&ppriv->vlan_rwsem);
 
+	rtnl_unlock();
+
 	if (result)
 		free_netdev(priv->dev);
 
-	rtnl_unlock();
-
 	return result;
 }
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/ib-ipoib-replace-list_del-of-the-neigh-list-with-list_del_init.patch queue-4.9/ib-ipoib-rtnl_unlock-can-not-come-after-free_netdev.patch queue-4.9/ib-ipoib-fix-deadlock-over-vlan_mutex.patch