Subject: [PATCH 3/7] netpoll: Fix device name check in netpoll_setup()

From: Matthias Kaehlcke <[email-masked]>
Date: Tue, 25 Jul 2017 11:36:25 -0700

commit 0c3a8f8b8fabff4f3ad2dd7b95ae0e90cdd1aebb upstream.

Apparently netpoll_setup() assumes that netpoll.dev_name is a pointer
when checking if the device name is set:

if (np->dev_name) {
  ...

However the field is a character array, therefore the condition always
yields true. Check instead whether the first byte of the array has a
non-zero value.

Signed-off-by: Matthias Kaehlcke <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
Signed-off-by: Nathan Chancellor <[email-masked]>
---
 net/core/netpoll.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 457f882b0f7b..9b2d61120c0d 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -666,7 +666,7 @@ int netpoll_setup(struct netpoll *np)
 	int err;
 
 	rtnl_lock();
-	if (np->dev_name) {
+	if (np->dev_name[0]) {
 		struct net *net = current->nsproxy->net_ns;
 		ndev = __dev_get_by_name(net, np->dev_name);
 	}
-- 
2.21.0