From a55acf28467a6e0637a1d321efa414556a13a2fd Mon Sep 17 00:00:00 2001
From: Sven Schnelle <svens@stackframe.org>
Date: Mon, 23 Nov 2015 15:49:53 +0100
Subject: [PATCH] bcwc_pcie: check return value from
 bcwc_channel_ringbuf_send()

It might return NULL, which would cause a kernel crash.
---
 bcwc_isp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/bcwc_isp.c b/bcwc_isp.c
index a24f39b..7e19d7f 100644
--- a/bcwc_isp.c
+++ b/bcwc_isp.c
@@ -297,6 +297,10 @@ int bcwc_isp_cmd(struct bcwc_private *dev_priv, enum bcwc_isp_cmds command, void
 	entry = bcwc_channel_ringbuf_send(dev_priv, dev_priv->channel_io,
 		request->offset, request_len + 8, (response_len ? *response_len : 0) + 8);
 
+	if (!entry) {
+		ret = -EIO;
+		goto out;
+	}
 	if (command == CISP_CMD_POWER_DOWN) {
 		/* powerdown doesn't seem to generate a response */
 		ret = 0;