Hi Mikhail, Thanks for your patch. Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx> writes: > Dereference of null pointer in the __gb_lights_flash_brightness_set function. > Assigning the channel the result of executing the get_channel_from_mode function > without checking for NULL may result in an error. > > Found by Linux Verification Center (linuxtesting.org) with SVACE. > > Fixes: 2870b52bae4c ("greybus: lights: add lights implementation") > Signed-off-by: Mikhail Lobanov <m.lobanov@xxxxxxxxxxxx> Yeah, at the time when this was implemented I recall that we could only set the brightness of the torch mode in a flash led, not in the flash only mode. So, if we were getting here was that for sure we had a torch channel and get_channel_from_mode will always find a channel, so never returning null here. but yeah, this is safer. but maybe just do something like the bellow would be simpler: modified 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); what do you think? Cheers, Rui > --- > drivers/staging/greybus/light.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/staging/greybus/light.c b/drivers/staging/greybus/light.c > index 87d36948c610..929514350947 100644 > --- a/drivers/staging/greybus/light.c > +++ b/drivers/staging/greybus/light.c > @@ -148,10 +148,15 @@ static int __gb_lights_flash_brightness_set(struct gb_channel *channel) > GB_CHANNEL_MODE_TORCH); > > /* For not flash we need to convert brightness to intensity */ > - intensity = channel->intensity_uA.min + > + > + if (channel) { > + intensity = channel->intensity_uA.min + > (channel->intensity_uA.step * channel->led->brightness); > > - return __gb_lights_flash_intensity_set(channel, intensity); > + return __gb_lights_flash_intensity_set(channel, intensity); > + } > + > + return 0; > } > #else > static struct gb_channel *get_channel_from_cdev(struct led_classdev *cdev) > -- > 2.43.0 _______________________________________________ greybus-dev mailing list -- greybus-dev@xxxxxxxxxxxxxxxx To unsubscribe send an email to greybus-dev-leave@xxxxxxxxxxxxxxxx