On 3/25/24 1:50 PM, Greg Kroah-Hartman wrote:
On Mon, Mar 25, 2024 at 01:31:34PM -0500, Alex Elder wrote: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().The huge majority of running Linux systems in the world run with panic-on-warn enabled, including the one in your pocket :(
I did not know that. Then WARN_ON() is no better than BUG_ON(). I'm still learning. Thank you. -Alex
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.Making noise by rebooting the box is not good. thanks, greg k-h
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