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 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
