greybus: lights: check return of get_channel_from_mode

If channel for the given node is not found we return null from
get_channel_from_mode. Make sure we validate the return pointer
before using it in two of the missing places.

This was originally reported in [0]:
Found by Linux Verification Center (linuxtesting.org) with SVACE.

[0] https://lore.kernel.org/all/[email protected]

Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")
Reported-by: Mikhail Lobanov <[email protected]>
Suggested-by: Mikhail Lobanov <[email protected]>
Suggested-by: Alex Elder <[email protected]>
Signed-off-by: Rui Miguel Silva <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

1 files changed, 7 insertions, 1 deletions

diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
index a5c2fe963866..00360f4a0485 100644
--- a/drivers/staging/greybus/light.c
+++ b/drivers/staging/greybus/light.c
@@ -142,6 +142,9 @@ static int __gb_lights_flash_brightness_set(struct gb_channel *channel)
 		channel = get_channel_from_mode(channel->light,
 						GB_CHANNEL_MODE_TORCH);
 
+	if (!channel)
+		return -EINVAL;
+
 	/* For not flash we need to convert brightness to intensity */
 	intensity = channel->intensity_uA.min +
 			(channel->intensity_uA.step * channel->led->brightness);
@@ -528,7 +531,10 @@ static int gb_lights_light_v4l2_register(struct gb_light *light)
 	}
 
 	channel_flash = get_channel_from_mode(light, GB_CHANNEL_MODE_FLASH);
-	WARN_ON(!channel_flash);
+	if (!channel_flash) {
+		dev_err(dev, "failed to get flash channel from mode\n");
+		return -EINVAL;
+	}
 
 	fled = &channel_flash->fled;