netpoll: Fix device name check in netpoll_setup()

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 <mka@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 457f882..9b2d611 100644 (file)
--- 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);
        }