[PATCH 3.12 095/113] Staging: vt6655-6: potential NULL dereference in hostap_disable_hostapd()

[Jiri Slaby]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit cb4855b49deb1acce27706ad9509d63c4fe8e988 upstream.

We fixed this to use free_netdev() instead of kfree() but unfortunately
free_netdev() doesn't accept NULL pointers.  Smatch complains about
this, it's not something I discovered through testing.

Fixes: 3030d40b5036 ('staging: vt6655: use free_netdev instead of kfree')
Fixes: 0a438d5b381e ('staging: vt6656: use free_netdev instead of kfree')
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 drivers/staging/vt6655/hostap.c | 3 ++-
 drivers/staging/vt6656/hostap.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/vt6655/hostap.c b/drivers/staging/vt6655/hostap.c
index 8acff44a9e75..3f6c96cf8ebe 100644
--- a/drivers/staging/vt6655/hostap.c
+++ b/drivers/staging/vt6655/hostap.c
@@ -143,7 +143,8 @@ static int hostap_disable_hostapd(PSDevice pDevice, int rtnl_locked)
 		DBG_PRT(MSG_LEVEL_DEBUG, KERN_INFO "%s: Netdevice %s unregistered\n",
 			pDevice->dev->name, pDevice->apdev->name);
 	}
-	free_netdev(pDevice->apdev);
+	if (pDevice->apdev)
+		free_netdev(pDevice->apdev);
 	pDevice->apdev = NULL;
 	pDevice->bEnable8021x = false;
 	pDevice->bEnableHostWEP = false;
diff --git a/drivers/staging/vt6656/hostap.c b/drivers/staging/vt6656/hostap.c
index c699a3058b39..cfffdd20e435 100644
--- a/drivers/staging/vt6656/hostap.c
+++ b/drivers/staging/vt6656/hostap.c
@@ -133,7 +133,8 @@ static int hostap_disable_hostapd(struct vnt_private *pDevice, int rtnl_locked)
             DBG_PRT(MSG_LEVEL_DEBUG, KERN_INFO "%s: Netdevice %s unregistered\n",
 		       pDevice->dev->name, pDevice->apdev->name);
 	}
-	free_netdev(pDevice->apdev);
+	if (pDevice->apdev)
+		free_netdev(pDevice->apdev);
 	pDevice->apdev = NULL;
     pDevice->bEnable8021x = false;
     pDevice->bEnableHostWEP = false;
-- 
2.12.0