Re: [PATCH] leds: fix a missing check of return value of lp55xx_read

From: Jacek Anaszewski
Date: Fri Dec 28 2018 - 11:53:39 EST

Hi Kangjie,

Thank you for the patch.

On 12/26/18 5:18 AM, Kangjie Lu wrote:
When lp55xx_read() fails, "status" is an uninitialized variable and thus
may contain random value; using it leads to undefined behaviors.

The fix inserts a check for the return value of lp55xx_read: if it
fails, returns with its error code.

Signed-off-by: Kangjie Lu <kjlu@xxxxxxx>
drivers/leds/leds-lp5523.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/leds/leds-lp5523.c b/drivers/leds/leds-lp5523.c
index a2e74feee2b2..fd64df5a57a5 100644
--- a/drivers/leds/leds-lp5523.c
+++ b/drivers/leds/leds-lp5523.c
@@ -318,7 +318,9 @@ static int lp5523_init_program_engine(struct lp55xx_chip *chip)
/* Let the programs run for couple of ms and check the engine status */
usleep_range(3000, 6000);
- lp55xx_read(chip, LP5523_REG_STATUS, &status);
+ ret = lp55xx_read(chip, LP5523_REG_STATUS, &status);
+ if (ret)
+ return ret;
status &= LP5523_ENG_STATUS_MASK;
if (status != LP5523_ENG_STATUS_MASK) {

Applied to fixes-for-4.21 branch of linux-leds.git.

Best regards,
Jacek Anaszewski