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>
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 31e047d..501e451 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -309,8 +309,8 @@
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)