Patch "IB/ipoib: Replace list_del of the neigh->list with list_del_init" has been added to the 4.4-stable tree

Patch "IB/ipoib: Replace list_del of the neigh->list with list_del_init" has been added to the 4.4-stable tree

[gregkh]

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

    IB/ipoib: Replace list_del of the neigh->list with list_del_init

to the 4.4-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-replace-list_del-of-the-neigh-list-with-list_del_init.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 Thu Oct  5 10:49:14 CEST 2017
From: Feras Daoud <ferasda@mellanox.com>
Date: Wed, 28 Dec 2016 14:47:27 +0200
Subject: IB/ipoib: Replace list_del of the neigh->list with list_del_init

From: Feras Daoud <ferasda@mellanox.com>


[ Upstream commit c586071d1dc8227a7182179b8e50ee92cc43f6d2 ]

In order to resolve a situation where a few process delete
the same list element in sequence and cause panic, list_del
is replaced with list_del_init. In this case if the first
process that calls list_del releases the lock before acquiring
it again, other processes who can acquire the lock will call
list_del_init.

Fixes: b63b70d87741 ("IPoIB: Use a private hash table for path lookup")
Signed-off-by: Feras Daoud <ferasda@mellanox.com>
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Reviewed-by: Alex Vesker <valex@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Reviewed-by: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/infiniband/ulp/ipoib/ipoib_main.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c
@@ -1239,7 +1239,7 @@ static void __ipoib_reap_neigh(struct ip
 						   rcu_dereference_protected(neigh->hnext,
 									     lockdep_is_held(&priv->lock)));
 				/* remove from path/mc list */
-				list_del(&neigh->list);
+				list_del_init(&neigh->list);
 				call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 			} else {
 				np = &neigh->hnext;
@@ -1406,7 +1406,7 @@ void ipoib_neigh_free(struct ipoib_neigh
 					   rcu_dereference_protected(neigh->hnext,
 								     lockdep_is_held(&priv->lock)));
 			/* remove from parent list */
-			list_del(&neigh->list);
+			list_del_init(&neigh->list);
 			call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 			return;
 		} else {
@@ -1491,7 +1491,7 @@ void ipoib_del_neighs_by_gid(struct net_
 						   rcu_dereference_protected(neigh->hnext,
 									     lockdep_is_held(&priv->lock)));
 				/* remove from parent list */
-				list_del(&neigh->list);
+				list_del_init(&neigh->list);
 				call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 			} else {
 				np = &neigh->hnext;
@@ -1533,7 +1533,7 @@ static void ipoib_flush_neighs(struct ip
 					   rcu_dereference_protected(neigh->hnext,
 								     lockdep_is_held(&priv->lock)));
 			/* remove from path/mc list */
-			list_del(&neigh->list);
+			list_del_init(&neigh->list);
 			call_rcu(&neigh->rcu, ipoib_neigh_reclaim);
 		}
 	}


Patches currently in stable-queue which might be from ferasda@mellanox.com are

queue-4.4/ib-ipoib-replace-list_del-of-the-neigh-list-with-list_del_init.patch
queue-4.4/ib-ipoib-rtnl_unlock-can-not-come-after-free_netdev.patch
queue-4.4/ib-ipoib-fix-deadlock-over-vlan_mutex.patch