From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 10 May 2011 19:26:06 +0000 (-0700)
Subject: net: dev_close() should check IFF_UP
X-Git-Url: http://git.alex.org.uk

net: dev_close() should check IFF_UP

BugLink: http://bugs.launchpad.net/bugs/788691

commit e14a599335427f81bbb0008963e59aa9c6449dce upstream.

Commit 443457242beb (factorize sync-rcu call in
unregister_netdevice_many) mistakenly removed one test from dev_close()

Following actions trigger a BUG :

modprobe bonding
modprobe dummy
ifconfig bond0 up
ifenslave bond0 dummy0
rmmod dummy

dev_close() must not close a non IFF_UP device.

With help from Frank Blaschka and Einar EL Lueck

Reported-by: Frank Blaschka <blaschka@linux.vnet.ibm.com>
Reported-by: Einar EL Lueck <ELELUECK@de.ibm.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Steve Conklin <sconklin@canonical.com>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index 6561021..af0995d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1332,11 +1332,13 @@ int dev_close_many(struct list_head *head)
  */
 int dev_close(struct net_device *dev)
 {
-	LIST_HEAD(single);
+	if (dev->flags & IFF_UP) {
+		LIST_HEAD(single);
 
-	list_add(&dev->unreg_list, &single);
-	dev_close_many(&single);
-	list_del(&single);
+		list_add(&dev->unreg_list, &single);
+		dev_close_many(&single);
+		list_del(&single);
+	}
 	return 0;
 }
 EXPORT_SYMBOL(dev_close);