[PATCH 3.16.y-ckt 041/185] staging: vt6655: device_rx_srv check sk_buff is NULL

[Luis Henriques]

3.16.7-ckt15 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Malcolm Priestley <tvboxspy at gmail.com>

commit b5eeed8cb6097c8ea660b6598d36fdbb94065a22 upstream.

There is a small chance that pRD->pRDInfo->skb could go NULL
while the interrupt is processing.

Put NULL check on loop to break out.

Signed-off-by: Malcolm Priestley <tvboxspy at gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/staging/vt6655/device_main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/staging/vt6655/device_main.c b/drivers/staging/vt6655/device_main.c
index 5a5fd937a442..e3ae2599a2b7 100644
--- a/drivers/staging/vt6655/device_main.c
+++ b/drivers/staging/vt6655/device_main.c
@@ -1402,6 +1402,10 @@ static int device_rx_srv(PSDevice pDevice, unsigned int uIdx) {
 	     pRD = pRD->next) {
 		if (works++ > 15)
 			break;
+
+		if (!pRD->pRDInfo->skb)
+			break;
+
 		if (device_receive_frame(pDevice, pRD)) {
 			if (!device_alloc_rx_buf(pDevice, pRD)) {
 				DBG_PRT(MSG_LEVEL_ERR, KERN_ERR