net: dev_close() should check IFF_UP

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>

diff --git a/net/core/dev.c b/net/core/dev.c
index 856b6ee9a1d5d5c1d4347d54048ac4f5d6bc73a1..92009440d28bedfda27927be81f59a5791f9dc2c 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1284,11 +1284,13 @@ static 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);