[PATCH] hwmon: (w83793) release probe data through kref

[PATCH] hwmon: (w83793) release probe data through kref

[Guangshuo Li]

w83793_probe() initializes data->kref to manage the lifetime of the
driver data. The normal remove path drops the driver-owned reference
with kref_put(), while watchdog users take and release additional
references through the same kref.

However, the probe error path still frees data directly with kfree().
This bypasses the kref-managed lifetime and discards the initial
reference without a matching kref_put(), leaving the reference
accounting unbalanced.

Drop the probe-owned reference with kref_put() instead and let
w83793_release_resources() perform the final free, matching the normal
remove path.

This issue was found by manual code inspection.

Fixes: 5852f9609d21 ("hwmon: (w83793) Add watchdog functionality")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
---
 drivers/hwmon/w83793.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/w83793.c b/drivers/hwmon/w83793.c
index a548586369e1..c6ef04c69856 100644
--- a/drivers/hwmon/w83793.c
+++ b/drivers/hwmon/w83793.c
@@ -1928,7 +1928,9 @@ static int w83793_probe(struct i2c_client *client)
 	for (i = 0; i < ARRAY_SIZE(w83793_temp); i++)
 		device_remove_file(dev, &w83793_temp[i].dev_attr);
 free_mem:
-	kfree(data);
+	mutex_lock(&watchdog_data_mutex);
+	kref_put(&data->kref, w83793_release_resources);
+	mutex_unlock(&watchdog_data_mutex);
 exit:
 	return err;
 }
-- 
2.43.0

Re: [PATCH] hwmon: (w83793) release probe data through kref

[Guenter Roeck]

On Mon, Sep 14, 2026 at 03:36:38PM +0800, Guangshuo Li wrote:
> w83793_probe() initializes data->kref to manage the lifetime of the
> driver data. The normal remove path drops the driver-owned reference
> with kref_put(), while watchdog users take and release additional
> references through the same kref.
> 
> However, the probe error path still frees data directly with kfree().
> This bypasses the kref-managed lifetime and discards the initial
> reference without a matching kref_put(), leaving the reference
> accounting unbalanced.
> 
> Drop the probe-owned reference with kref_put() instead and let
> w83793_release_resources() perform the final free, matching the normal
> remove path.
> 
> This issue was found by manual code inspection.
> 
> Fixes: 5852f9609d21 ("hwmon: (w83793) Add watchdog functionality")
> Cc: stable@vger.kernel.org
> Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>

Applied.

Thanks,
Guenter