net: deinit automatic LIST_HEAD

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 <[email protected]>
Tested-by: Michal Hocko <[email protected]>
Reported-by: Eric W. Biderman <[email protected]>
Tested-by: Eric W. Biderman <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Octavian Purdila <[email protected]>
CC: stable <[email protected]> [.33+]
Signed-off-by: David S. Miller <[email protected]>

diff --git a/net/core/dev.c b/net/core/dev.c
index a18c1643ea9ff8a242d68f72593dbd9ab79d23d8..8ae6631abcc2093fe2ce9929f255be7e9c1eaff1 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5066,6 +5066,7 @@ static void rollback_registered(struct net_device *dev)
 
        list_add(&dev->unreg_list, &single);
        rollback_registered_many(&single);
+       list_del(&single);
 }
 
 unsigned long netdev_fix_features(unsigned long features, const char *name)
@@ -6219,6 +6220,7 @@ 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();
 }