[PATCH] hwmon: add a check of devm_add_action

[PATCH] hwmon: add a check of devm_add_action

[Kang Chen]

devm_add_action may fails, do the cleanup when if fails.

Signed-off-by: Kang Chen <void0red@gmail.com>
---
 drivers/hwmon/g762.c        | 6 +++++-
 drivers/hwmon/nzxt-smart2.c | 4 +++-
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/g762.c b/drivers/hwmon/g762.c
index 64a0599b2..d06d8bf20 100644
--- a/drivers/hwmon/g762.c
+++ b/drivers/hwmon/g762.c
@@ -620,7 +620,11 @@ static int g762_of_clock_enable(struct i2c_client *client)
 	data = i2c_get_clientdata(client);
 	data->clk = clk;
 
-	devm_add_action(&client->dev, g762_of_clock_disable, data);
+	ret = devm_add_action(&client->dev, g762_of_clock_disable, data);
+	if (ret) {
+		dev_err(&client->dev, "failed to add disable clock action\n");
+		goto clk_unprep;
+	}
 	return 0;
 
  clk_unprep:
diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
index 2b93ba896..725974cb3 100644
--- a/drivers/hwmon/nzxt-smart2.c
+++ b/drivers/hwmon/nzxt-smart2.c
@@ -737,8 +737,10 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
 	init_waitqueue_head(&drvdata->wq);
 
 	mutex_init(&drvdata->mutex);
-	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
+	ret = devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
 			&drvdata->mutex);
+	if (ret)
+		return ret;
 
 	ret = hid_parse(hdev);
 	if (ret)
-- 
2.34.1

Re: [PATCH] hwmon: add a check of devm_add_action

[Guenter Roeck]

On 2/26/23 18:17, Kang Chen wrote:
> devm_add_action may fails, do the cleanup when if fails.
> 
> Signed-off-by: Kang Chen <void0red@gmail.com>
> ---
>   drivers/hwmon/g762.c        | 6 +++++-
>   drivers/hwmon/nzxt-smart2.c | 4 +++-

Two patches, please.

Guenter

>   2 files changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/g762.c b/drivers/hwmon/g762.c
> index 64a0599b2..d06d8bf20 100644
> --- a/drivers/hwmon/g762.c
> +++ b/drivers/hwmon/g762.c
> @@ -620,7 +620,11 @@ static int g762_of_clock_enable(struct i2c_client *client)
>   	data = i2c_get_clientdata(client);
>   	data->clk = clk;
>   
> -	devm_add_action(&client->dev, g762_of_clock_disable, data);
> +	ret = devm_add_action(&client->dev, g762_of_clock_disable, data);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to add disable clock action\n");
> +		goto clk_unprep;
> +	}
>   	return 0;
>   
>    clk_unprep:
> diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
> index 2b93ba896..725974cb3 100644
> --- a/drivers/hwmon/nzxt-smart2.c
> +++ b/drivers/hwmon/nzxt-smart2.c
> @@ -737,8 +737,10 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
>   	init_waitqueue_head(&drvdata->wq);
>   
>   	mutex_init(&drvdata->mutex);
> -	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
> +	ret = devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
>   			&drvdata->mutex);
> +	if (ret)
> +		return ret;
>   
>   	ret = hid_parse(hdev);
>   	if (ret)

[PATCH v2 1/2] hwmon: g762: add a check of devm_add_action in g762_of_clock_enable

[void0red]

From: Kang Chen <void0red@gmail.com>

devm_add_action may fails, check it and do the cleanup.

Signed-off-by: Kang Chen <void0red@gmail.com>
---
v2 -> v1: split the patch

 drivers/hwmon/g762.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/g762.c b/drivers/hwmon/g762.c
index 64a0599b2..e2c3c34f0 100644
--- a/drivers/hwmon/g762.c
+++ b/drivers/hwmon/g762.c
@@ -620,7 +620,12 @@ static int g762_of_clock_enable(struct i2c_client *client)
 	data = i2c_get_clientdata(client);
 	data->clk = clk;
 
-	devm_add_action(&client->dev, g762_of_clock_disable, data);
+	ret = devm_add_action(&client->dev, g762_of_clock_disable, data);
+	if (ret) {
+		dev_err(&client->dev, "failed to add disable clock action\n");
+		goto clk_unprep;
+	}
+
 	return 0;
 
  clk_unprep:
-- 
2.34.1

[PATCH v2 2/2] hwmon: nzxt-smart2: add a check of devm_add_action in nzxt_smart2_hid_probe

[void0red]

From: Kang Chen <void0red@gmail.com>

devm_add_action may fails, check it and return early.

Signed-off-by: Kang Chen <void0red@gmail.com>
---
v2 -> v1: split the patch

 drivers/hwmon/nzxt-smart2.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
index 2b93ba896..725974cb3 100644
--- a/drivers/hwmon/nzxt-smart2.c
+++ b/drivers/hwmon/nzxt-smart2.c
@@ -737,8 +737,10 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
 	init_waitqueue_head(&drvdata->wq);
 
 	mutex_init(&drvdata->mutex);
-	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
+	ret = devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
 			&drvdata->mutex);
+	if (ret)
+		return ret;
 
 	ret = hid_parse(hdev);
 	if (ret)
-- 
2.34.1

Re: [PATCH v2 2/2] hwmon: nzxt-smart2: add a check of devm_add_action in nzxt_smart2_hid_probe

[Guenter Roeck]

On 2/26/23 19:09, void0red wrote:
> From: Kang Chen <void0red@gmail.com>
> 
> devm_add_action may fails, check it and return early.
> 
> Signed-off-by: Kang Chen <void0red@gmail.com>
> ---
> v2 -> v1: split the patch
> 
>   drivers/hwmon/nzxt-smart2.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
> index 2b93ba896..725974cb3 100644
> --- a/drivers/hwmon/nzxt-smart2.c
> +++ b/drivers/hwmon/nzxt-smart2.c
> @@ -737,8 +737,10 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
>   	init_waitqueue_head(&drvdata->wq);
>   
>   	mutex_init(&drvdata->mutex);
> -	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
> +	ret = devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
>   			&drvdata->mutex);

Please watch for multi-line alignment. Also, turns out the original
code is wrong: Type casting a function pointer argument like this,
while it typically works in practice, is undefined in C. The function
pointer passed to devm_add_action() needs to point to a local
function with void * argument, and that function needs to call
mutex_destroy() with the same argument. Also, based on the context,
this needs to call devm_add_action_or_reset() to ensure that
the destroy function is called on error.

Thanks,
Guenter

> +	if (ret)
> +		return ret;
>   
>   	ret = hid_parse(hdev);
>   	if (ret)

[PATCH v3] hwmon: nzxt-smart2: handle failure of devm_add_action in nzxt_smart2_hid_probe

[void0red]

From: Kang Chen <void0red@gmail.com>

1. replace the devm_add_action with devm_add_action_or_reset to ensure
the mutex lock can be destroyed when it fails.
2. use local wrapper function mutex_fini instead of mutex_destroy to
avoid undefined behaviours.
3. add a check of devm_add_action_or_reset and return early when it fails.

Link: https://lore.kernel.org/all/f5043281-9b3e-e454-16fe-ef4cde36dfdb@roeck-us.net
Signed-off-by: Kang Chen <void0red@gmail.com>
---
v3 -> v2: use local function and devm_add_action_or_rest
v2 -> v1: split the patch

 drivers/hwmon/nzxt-smart2.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
index 2b93ba896..340002581 100644
--- a/drivers/hwmon/nzxt-smart2.c
+++ b/drivers/hwmon/nzxt-smart2.c
@@ -721,6 +721,11 @@ static int __maybe_unused nzxt_smart2_hid_reset_resume(struct hid_device *hdev)
 	return init_device(drvdata, drvdata->update_interval);
 }
 
+static void mutex_fini(void *lock)
+{
+	mutex_destroy(lock);
+}
+
 static int nzxt_smart2_hid_probe(struct hid_device *hdev,
 				 const struct hid_device_id *id)
 {
@@ -737,8 +742,9 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
 	init_waitqueue_head(&drvdata->wq);
 
 	mutex_init(&drvdata->mutex);
-	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
-			&drvdata->mutex);
+	ret = devm_add_action_or_reset(&hdev->dev, mutex_fini, &drvdata->mutex);
+	if (ret)
+		return ret;
 
 	ret = hid_parse(hdev);
 	if (ret)
-- 
2.34.1

Re: [PATCH v3] hwmon: nzxt-smart2: handle failure of devm_add_action in nzxt_smart2_hid_probe

[Guenter Roeck]

On Mon, Feb 27, 2023 at 05:15:34PM +0800, void0red wrote:
> From: Kang Chen <void0red@gmail.com>
> 
> 1. replace the devm_add_action with devm_add_action_or_reset to ensure
> the mutex lock can be destroyed when it fails.
> 2. use local wrapper function mutex_fini instead of mutex_destroy to
> avoid undefined behaviours.
> 3. add a check of devm_add_action_or_reset and return early when it fails.
> 
> Link: https://lore.kernel.org/all/f5043281-9b3e-e454-16fe-ef4cde36dfdb@roeck-us.net
> Signed-off-by: Kang Chen <void0red@gmail.com>

Applied.

Thanks,
Guenter

> ---
> v3 -> v2: use local function and devm_add_action_or_rest
> v2 -> v1: split the patch
> 
>  drivers/hwmon/nzxt-smart2.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/nzxt-smart2.c b/drivers/hwmon/nzxt-smart2.c
> index 2b93ba896..340002581 100644
> --- a/drivers/hwmon/nzxt-smart2.c
> +++ b/drivers/hwmon/nzxt-smart2.c
> @@ -721,6 +721,11 @@ static int __maybe_unused nzxt_smart2_hid_reset_resume(struct hid_device *hdev)
>  	return init_device(drvdata, drvdata->update_interval);
>  }
>  
> +static void mutex_fini(void *lock)
> +{
> +	mutex_destroy(lock);
> +}
> +
>  static int nzxt_smart2_hid_probe(struct hid_device *hdev,
>  				 const struct hid_device_id *id)
>  {
> @@ -737,8 +742,9 @@ static int nzxt_smart2_hid_probe(struct hid_device *hdev,
>  	init_waitqueue_head(&drvdata->wq);
>  
>  	mutex_init(&drvdata->mutex);
> -	devm_add_action(&hdev->dev, (void (*)(void *))mutex_destroy,
> -			&drvdata->mutex);
> +	ret = devm_add_action_or_reset(&hdev->dev, mutex_fini, &drvdata->mutex);
> +	if (ret)
> +		return ret;
>  
>  	ret = hid_parse(hdev);
>  	if (ret)

Re: [PATCH v2 1/2] hwmon: g762: add a check of devm_add_action in g762_of_clock_enable

[Guenter Roeck]

On Mon, Feb 27, 2023 at 11:09:12AM +0800, void0red wrote:
> From: Kang Chen <void0red@gmail.com>
> 
> devm_add_action may fails, check it and do the cleanup.
> 
> Signed-off-by: Kang Chen <void0red@gmail.com>

Applied.

Thanks,
Guenter

> ---
> v2 -> v1: split the patch
> 
>  drivers/hwmon/g762.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/g762.c b/drivers/hwmon/g762.c
> index 64a0599b2..e2c3c34f0 100644
> --- a/drivers/hwmon/g762.c
> +++ b/drivers/hwmon/g762.c
> @@ -620,7 +620,12 @@ static int g762_of_clock_enable(struct i2c_client *client)
>  	data = i2c_get_clientdata(client);
>  	data->clk = clk;
>  
> -	devm_add_action(&client->dev, g762_of_clock_disable, data);
> +	ret = devm_add_action(&client->dev, g762_of_clock_disable, data);
> +	if (ret) {
> +		dev_err(&client->dev, "failed to add disable clock action\n");
> +		goto clk_unprep;
> +	}
> +
>  	return 0;
>  
>   clk_unprep: