[PATCH v2] backlight: pm8941: Add NULL check in wled_configure()

[PATCH v2] backlight: pm8941: Add NULL check in wled_configure()

[Henry Martin]

devm_kasprintf() return NULL if memory allocation fails. Currently,
wled_configure() does not check for this case, leading to a possible NULL
pointer dereference.

Add NULL check after devm_kasprintf() to prevent this issue.

Fixes: f86b77583d88 ("backlight: pm8941: Convert to using %pOFn instead of device_node.name")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
V1 -> V2: Fix commit message to use imperative mood and wrap lines to 75
characters.

 drivers/video/backlight/qcom-wled.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/video/backlight/qcom-wled.c b/drivers/video/backlight/qcom-wled.c
index 9afe701b2a1b..a63bb42c8f8b 100644
--- a/drivers/video/backlight/qcom-wled.c
+++ b/drivers/video/backlight/qcom-wled.c
@@ -1406,9 +1406,11 @@ static int wled_configure(struct wled *wled)
 	wled->ctrl_addr = be32_to_cpu(*prop_addr);
 
 	rc = of_property_read_string(dev->of_node, "label", &wled->name);
-	if (rc)
+	if (rc) {
 		wled->name = devm_kasprintf(dev, GFP_KERNEL, "%pOFn", dev->of_node);
-
+		if (!wled->name)
+			return -ENOMEM;
+	}
 	switch (wled->version) {
 	case 3:
 		u32_opts = wled3_opts;
-- 
2.34.1

Re: [PATCH v2] backlight: pm8941: Add NULL check in wled_configure()

[Markus Elfring]

> devm_kasprintf() return NULL if memory allocation fails. Currently,

                 call?                               failed?


> wled_configure() does not check for this case, leading to a possible NULL
> pointer dereference.

You may omit the word “possible” in such a change description.
(Would questionable data processing happen in other function implementations?)


> Add NULL check after devm_kasprintf() to prevent this issue.

Do you complete the error/exception handling also with the statement “return -ENOMEM;”?

Regards,
Markus

Re: [PATCH v2] backlight: pm8941: Add NULL check in wled_configure()

[Dmitry Baryshkov]

On Mon, Mar 31, 2025 at 10:16:54PM +0800, Henry Martin wrote:
> devm_kasprintf() return NULL if memory allocation fails. Currently,
> wled_configure() does not check for this case, leading to a possible NULL
> pointer dereference.
> 
> Add NULL check after devm_kasprintf() to prevent this issue.
> 
> Fixes: f86b77583d88 ("backlight: pm8941: Convert to using %pOFn instead of device_node.name")
> Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
> ---
> V1 -> V2: Fix commit message to use imperative mood and wrap lines to 75
> characters.
> 
>  drivers/video/backlight/qcom-wled.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

-- 
With best wishes
Dmitry