diff mbox series

backlight: lp855x: fix unintialized function return

Message ID 20230811131600.2380519-1-arnd@kernel.org (mailing list archive)
State New, archived
Headers show
Series backlight: lp855x: fix unintialized function return | expand

Commit Message

Arnd Bergmann Aug. 11, 2023, 1:15 p.m. UTC 
From: Arnd Bergmann <arnd@arndb.de>

The function now returns an error code in some cases, but fails to initialize
it in others:

drivers/video/backlight/lp855x_bl.c:252:11: error: variable 'ret' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
        else if (lp->mode == REGISTER_BASED)
                 ^~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/video/backlight/lp855x_bl.c:256:9: note: uninitialized use occurs here
        return ret;
               ^~~
drivers/video/backlight/lp855x_bl.c:252:7: note: remove the 'if' if its condition is always true
        else if (lp->mode == REGISTER_BASED)
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since this case should not actually happen, return the -EINVAL code.

Fixes: 5145531be5fba ("backlight: lp855x: Catch errors when changing brightness")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/video/backlight/lp855x_bl.c | 2 ++
 1 file changed, 2 insertions(+)

Comments

Daniel Thompson Aug. 14, 2023, 8:41 a.m. UTC | #1 
On Fri, Aug 11, 2023 at 03:15:53PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> The function now returns an error code in some cases, but fails to initialize
> it in others:
>
> drivers/video/backlight/lp855x_bl.c:252:11: error: variable 'ret' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
>         else if (lp->mode == REGISTER_BASED)
>                  ^~~~~~~~~~~~~~~~~~~~~~~~~~
> drivers/video/backlight/lp855x_bl.c:256:9: note: uninitialized use occurs here
>         return ret;
>                ^~~
> drivers/video/backlight/lp855x_bl.c:252:7: note: remove the 'if' if its condition is always true
>         else if (lp->mode == REGISTER_BASED)
>              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Since this case should not actually happen, return the -EINVAL code.
>
> Fixes: 5145531be5fba ("backlight: lp855x: Catch errors when changing brightness")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

I think we already received a patch for this:
https://lore.kernel.org/lkml/20230809163825.GA5056@aspen.lan/T/


Daniel.
diff mbox series

Patch

diff --git a/drivers/video/backlight/lp855x_bl.c b/drivers/video/backlight/lp855x_bl.c
index 61a7f45bfad84..ea4fa69e49a70 100644
--- a/drivers/video/backlight/lp855x_bl.c
+++ b/drivers/video/backlight/lp855x_bl.c
@@ -252,6 +252,8 @@  static int lp855x_bl_update_status(struct backlight_device *bl)
 	else if (lp->mode == REGISTER_BASED)
 		ret = lp855x_write_byte(lp, lp->cfg->reg_brightness,
 					(u8)brightness);
+	else
+		ret = -EINVAL;
 
 	return ret;
 }