[PATCH] hwmon: pwm-fan: Add const to channels allocation type

[PATCH] hwmon: pwm-fan: Add const to channels allocation type

[Kees Cook]

From: Kees Cook <kees+treewide@kernel.org>

In preparation for making the devm_kmalloc family of allocators type
aware, we need to make sure that the returned type from the allocation
matches the type of the variable being assigned. (Before, the allocator
would always return "void *", which can be implicitly cast to any
pointer type.)

The assigned type is "const struct hwmon_channel_info **", but the
converted allocation type would be "struct hwmon_channel_info **", which
is the same type without the const qualifier. As there is no general way
to safely add const qualifiers, take the size from the assignment target
instead. No change in allocation size results.

Build tested ARCH=x86_64 allmodconfig with GCC 16.2.0:
drivers/hwmon/pwm-fan.o

Assisted-by: LLM coccinelle
Signed-off-by: Kees Cook <kees+treewide@kernel.org>
---
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: <linux-hwmon@vger.kernel.org>
---
 drivers/hwmon/pwm-fan.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 3b87f65bae05..db19a054f4f4 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -613,7 +613,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
 	}
 
 	channels = devm_kcalloc(dev, channel_count + 1,
-				sizeof(struct hwmon_channel_info *), GFP_KERNEL);
+				sizeof(*channels), GFP_KERNEL);
 	if (!channels)
 		return -ENOMEM;
 
-- 
2.34.1

Re: [PATCH] hwmon: pwm-fan: Add const to channels allocation type

[Guenter Roeck]

On Thu, Sep 17, 2026 at 02:14:18PM -0700, Kees Cook wrote:
> From: Kees Cook <kees+treewide@kernel.org>
> 
> In preparation for making the devm_kmalloc family of allocators type
> aware, we need to make sure that the returned type from the allocation
> matches the type of the variable being assigned. (Before, the allocator
> would always return "void *", which can be implicitly cast to any
> pointer type.)
> 
> The assigned type is "const struct hwmon_channel_info **", but the
> converted allocation type would be "struct hwmon_channel_info **", which
> is the same type without the const qualifier. As there is no general way
> to safely add const qualifiers, take the size from the assignment target
> instead. No change in allocation size results.
> 
> Build tested ARCH=x86_64 allmodconfig with GCC 16.2.0:
> drivers/hwmon/pwm-fan.o
> 
> Assisted-by: LLM coccinelle
> Signed-off-by: Kees Cook <kees+treewide@kernel.org>

Applied.

Thanks,
Guenter