net: deinit automatic LIST_HEAD

commit ceaaec98ad99859ac90ac6863ad0a6cd075d8e0e upstream.

commit 9b5e383c11b08784 (net: Introduce
unregister_netdevice_many()) left an active LIST_HEAD() in
rollback_registered(), with possible memory corruption.

Even if device is freed without touching its unreg_list (and therefore
touching the previous memory location holding LISTE_HEAD(single), better
close the bug for good, since its really subtle.

(Same fix for default_device_exit_batch() for completeness)

Reported-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Michal Hocko <mhocko@suse.cz>
Reported-by: Eric W. Biderman <ebiderman@xmission.com>
Tested-by: Eric W. Biderman <ebiderman@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
CC: Ingo Molnar <mingo@elte.hu>
CC: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/net/core/dev.c b/net/core/dev.c
index 6d1eefc258acf5022f5ef4792ad144ca90c92c6f..4d2f613342b9cbd125fb856e0c3ec916ce38d95c 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4846,6 +4846,7 @@ static void rollback_registered(struct net_device *dev)
 
        list_add(&dev->unreg_list, &single);
        rollback_registered_many(&single);
+       list_del(&single);
 }
 
 static void __netdev_init_queue_locks_one(struct net_device *dev,
@@ -5828,6 +5829,7 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
                }
        }
        unregister_netdevice_many(&dev_kill_list);
+       list_del(&dev_kill_list);
        rtnl_unlock();
 }