netconsole: avoid null pointer dereference at show_local_mac()

This patch avoids a null pointer dereference when we read local_mac 
for netconsole in configfs and shows default local mac address
value.

A null pointer dereference occurs when we call show_local_mac() via 
local_mac entry in configfs before we setup the content of netpoll
using netpoll_setup().

Signed-off-by: Keiichi KII <k-keiichi@bx.jp.nec.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Keiichi KII 2008-02-15 02:01:58 -08:00 committed by David S. Miller
parent b5c15fc004
commit 69c3683ca7

View File

@ -309,8 +309,8 @@ static ssize_t show_local_mac(struct netconsole_target *nt, char *buf)
struct net_device *dev = nt->np.dev;
DECLARE_MAC_BUF(mac);
return snprintf(buf, PAGE_SIZE, "%s\n",
print_mac(mac, dev->dev_addr));
return snprintf(buf, PAGE_SIZE, "%s\n", dev ?
print_mac(mac, dev->dev_addr) : "ff:ff:ff:ff:ff:ff");
}
static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf)