From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 17 Feb 2011 22:59:19 +0000 (+0000)
Subject: net: deinit automatic LIST_HEAD
X-Git-Tag: Ubuntu-5.4-5.4.0-11.14~22968^2
X-Git-Url: https://git.proxmox.com/?a=commitdiff_plain;h=ceaaec98ad99859ac90ac6863ad0a6cd075d8e0e;p=mirror_ubuntu-focal-kernel.git

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 <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>
CC: stable <stable@kernel.org> [.33+]
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index a18c1643ea9f..8ae6631abcc2 100644
--- 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();
 }