From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sun, 15 Nov 2009 23:30:24 +0000 (+0000)
Subject: net: Fix the rollback test in dev_change_name()
X-Git-Tag: v2.6.32-rc8~10^2~9
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=91e9c07bd635353d1a278bdb38dbb56ac371bcb8;p=karo-tx-linux.git

net: Fix the rollback test in dev_change_name()

net: Fix the rollback test in dev_change_name()

In dev_change_name() an err variable is used for storing the original
call_netdevice_notifiers() errno (negative) and testing for a rollback
error later, but the test for non-zero is wrong, because the err might
have positive value as well - from dev_alloc_name(). It means the
rollback for a netdevice with a number > 0 will never happen. (The err
test is reordered btw. to make it more readable.)

Signed-off-by: Jarek Poplawski <jarkao2@gmail.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 b8f74cfb1bfd..fe10551d3671 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -942,14 +942,15 @@ rollback:
 	ret = notifier_to_errno(ret);
 
 	if (ret) {
-		if (err) {
-			printk(KERN_ERR
-			       "%s: name change rollback failed: %d.\n",
-			       dev->name, ret);
-		} else {
+		/* err >= 0 after dev_alloc_name() or stores the first errno */
+		if (err >= 0) {
 			err = ret;
 			memcpy(dev->name, oldname, IFNAMSIZ);
 			goto rollback;
+		} else {
+			printk(KERN_ERR
+			       "%s: name change rollback failed: %d.\n",
+			       dev->name, ret);
 		}
 	}