On 3/25/24 12:25 PM, Greg Kroah-Hartman wrote:
On Thu, Mar 07, 2024 at 09:48:13AM +0000, Rui Miguel Silva wrote:
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/20240301190425.120605-1-m.lobanov@xxxxxxxxxxxx
Fixes: 2870b52bae4c ("greybus: lights: add lights implementation")
Reported-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
Suggested-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx>
Suggested-by: Alex Elder <elder@xxxxxxxx>
Signed-off-by: Rui Miguel Silva <rmfrfs@xxxxxxxxx>
---
drivers/staging/greybus/light.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c
index c6bd86a5335a..6f10b9e2c053 100644
--- a/drivers/staging/greybus/light.c
+++ b/drivers/staging/greybus/light.c
@@ -147,6 +147,9 @@ 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);
@@ -549,7 +552,8 @@ 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 (WARN_ON(!channel_flash))
+ return -EINVAL;
We should NOT crash machines just because of this, the WARN_ON() should
be removed and just properly handle the error please.
Greg, WARN_ON() doesn't normally crash the machine. That said,
it's reasonable to remove the WARN_ON().
I think the purpose of the warning is that this is a case that
should "never happen," so if it does, it's making some noise.
The only caller is gb_lights_light_register(), and it checks
for an error and does "properly handle" the\ error (assuming
any error meaning "light has no flash" is correct).
Rui, please weigh in.
-Alex
thanks,
greg k-h
