From: Gao feng <gaofeng@cn.fujitsu.com>
Date: Tue, 11 Oct 2011 16:08:11 +0000 (+0000)
Subject: netconsole: enable netconsole can make net_device refcnt incorrent
X-Git-Tag: v3.0.9~122
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=18743353b3154f0ff7c29f3c5ae3a8466a70d73a;p=karo-tx-linux.git

netconsole: enable netconsole can make net_device refcnt incorrent

[ Upstream commit d5123480b1d6f7d1a5fe1a13520cef88fb5d4c84 ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index dfc82720065a..4840ab7e7f8a 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -307,6 +307,11 @@ static ssize_t store_enabled(struct netconsole_target *nt,
 		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 */