[PATCH] media: uvcvideo: fix a crash in uvc_ctrl_init_ctrl()

[Dan Carpenter <dan.carpenter@oracle.com>]

There is a path where "mapping" is NULL when we try to process the
common mappings so it will crash.

Fixes: 86f7ef773156 ("media: uvcvideo: Add support for per-device control mapping overrides")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
This bug was previously reported by the kbuild bot and fixed in later
versions of the patchset.  The git log doesn't have a link to
lore.kernel.org but I suspect an earlier version got merged?

 drivers/media/usb/uvc/uvc_ctrl.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
index e4826a846861..00ea894e79fd 100644
--- a/drivers/media/usb/uvc/uvc_ctrl.c
+++ b/drivers/media/usb/uvc/uvc_ctrl.c
@@ -2413,9 +2413,9 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
 {
 	const struct uvc_control_info *info = uvc_ctrls;
 	const struct uvc_control_info *iend = info + ARRAY_SIZE(uvc_ctrls);
-	const struct uvc_control_mapping *mapping = uvc_ctrl_mappings;
-	const struct uvc_control_mapping *mend =
-		mapping + ARRAY_SIZE(uvc_ctrl_mappings);
+	const struct uvc_control_mapping *mapping;
+	const struct uvc_control_mapping *mend;
+	unsigned int i;
 
 	/*
 	 * XU controls initialization requires querying the device for control
@@ -2453,7 +2453,6 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
 	 */
 	if (chain->dev->info->mappings) {
 		bool custom = false;
-		unsigned int i;
 
 		for (i = 0; (mapping = chain->dev->info->mappings[i]); ++i) {
 			if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
@@ -2468,7 +2467,8 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
 	}
 
 	/* Process common mappings next. */
-	for (; mapping < mend; ++mapping) {
+	for (i = 0; i < ARRAY_SIZE(uvc_ctrl_mappings); i++) {
+		mapping = &uvc_ctrl_mappings[i];
 		if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
 		    ctrl->info.selector == mapping->selector)
 			__uvc_ctrl_add_mapping(chain, ctrl, mapping);
-- 
2.35.1