netconsole: enable netconsole can make net_device refcnt incorrent
There is no check if netconsole is enabled current.
so when exec echo 1 > enabled;
the reference of net_device will increment always.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Acked-by: Flavio Leitner <fbl@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index ed2a397..e888202 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -307,6 +307,11 @@
return err;
if (enabled < 0 || enabled > 1)
return -EINVAL;
+ if (enabled == nt->enabled) {
+ printk(KERN_INFO "netconsole: network logging has already %s\n",
+ nt->enabled ? "started" : "stopped");
+ return -EINVAL;
+ }
if (enabled) { /* 1 */