[PATCH] backlight: mp3309c: fix uninitialized local variable

[PATCH] backlight: mp3309c: fix uninitialized local variable

[Flavio Suligoi]

In the function "pm3309c_parse_dt_node", when the dimming analog control
mode (by I2C messages) is enabled, the local variable "prop_levels" is
tested without any initialization, as indicated by the following smatch
warning (thanks to Dan Carpenter for the report):

drivers/video/backlight/mp3309c.c:279 pm3309c_parse_dt_node() error: uninitialized symbol 'prop_levels'.

To avoid any problem in case of undefined behavior, we need to initialize
it to "NULL".
For consistency, I also initialize the other similar variable
"prop_pwms" in the same way.

Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
---
 drivers/video/backlight/mp3309c.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/mp3309c.c b/drivers/video/backlight/mp3309c.c
index 3fe4469ef43f..733cad1dd15c 100644
--- a/drivers/video/backlight/mp3309c.c
+++ b/drivers/video/backlight/mp3309c.c
@@ -203,7 +203,8 @@ static int pm3309c_parse_dt_node(struct mp3309c_chip *chip,
 				 struct mp3309c_platform_data *pdata)
 {
 	struct device_node *node = chip->dev->of_node;
-	struct property *prop_pwms, *prop_levels;
+	struct property *prop_pwms = NULL;
+	struct property *prop_levels = NULL;
 	int length = 0;
 	int ret, i;
 	unsigned int num_levels, tmp_value;
-- 
2.34.1

[PATCH] backlight: mp3309c: fix uninitialized local variable

[Flavio Suligoi]

In the function "pm3309c_parse_dt_node", when the dimming analog control
mode (by I2C messages) is enabled, the local variable "prop_levels" is
tested without any initialization, as indicated by the following smatch
warning (thanks to Dan Carpenter for the report):

drivers/video/backlight/mp3309c.c:279 pm3309c_parse_dt_node() error: uninitialized symbol 'prop_levels'.

To avoid any problem in case of undefined behavior, we need to initialize
it to "NULL".
For consistency, I also initialize the other similar variable
"prop_pwms" in the same way.

Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
---
 drivers/video/backlight/mp3309c.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/mp3309c.c b/drivers/video/backlight/mp3309c.c
index 3fe4469ef43f..733cad1dd15c 100644
--- a/drivers/video/backlight/mp3309c.c
+++ b/drivers/video/backlight/mp3309c.c
@@ -203,7 +203,8 @@ static int pm3309c_parse_dt_node(struct mp3309c_chip *chip,
 				 struct mp3309c_platform_data *pdata)
 {
 	struct device_node *node = chip->dev->of_node;
-	struct property *prop_pwms, *prop_levels;
+	struct property *prop_pwms = NULL;
+	struct property *prop_levels = NULL;
 	int length = 0;
 	int ret, i;
 	unsigned int num_levels, tmp_value;
-- 
2.34.1

Re: [PATCH] backlight: mp3309c: fix uninitialized local variable

[Daniel Thompson]

On Tue, Nov 28, 2023 at 04:08:39PM +0100, Flavio Suligoi wrote:
> In the function "pm3309c_parse_dt_node", when the dimming analog control
> mode (by I2C messages) is enabled, the local variable "prop_levels" is
> tested without any initialization, as indicated by the following smatch
> warning (thanks to Dan Carpenter for the report):

Good to see credit for the reporter but please use a "Reported-by:" tag
for that. There should probably be a "Fixed:" tag too.


> drivers/video/backlight/mp3309c.c:279 pm3309c_parse_dt_node() error: uninitialized symbol 'prop_levels'.
>
> To avoid any problem in case of undefined behavior, we need to initialize
> it to "NULL".
> For consistency, I also initialize the other similar variable
> "prop_pwms" in the same way.

I don't love redundant initializations... but I can live with it ;-) .


Daniel.

Re: [PATCH] backlight: mp3309c: fix uninitialized local variable

[Daniel Thompson]

On Tue, Nov 28, 2023 at 04:08:39PM +0100, Flavio Suligoi wrote:
> In the function "pm3309c_parse_dt_node", when the dimming analog control
> mode (by I2C messages) is enabled, the local variable "prop_levels" is
> tested without any initialization, as indicated by the following smatch
> warning (thanks to Dan Carpenter for the report):

Good to see credit for the reporter but please use a "Reported-by:" tag
for that. There should probably be a "Fixed:" tag too.


> drivers/video/backlight/mp3309c.c:279 pm3309c_parse_dt_node() error: uninitialized symbol 'prop_levels'.
>
> To avoid any problem in case of undefined behavior, we need to initialize
> it to "NULL".
> For consistency, I also initialize the other similar variable
> "prop_pwms" in the same way.

I don't love redundant initializations... but I can live with it ;-) .


Daniel.