[PATCH] media: mgb4: Fix double debugfs remove

[PATCH] media: mgb4: Fix double debugfs remove

[tumic]

From: Martin Tůma <martin.tuma@digiteqautomotive.com>

Fixes an error where debugfs_remove_recursive() is called first on a parent
directory and then again on a child which causes a kernel panic.

Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com>
---
 drivers/media/pci/mgb4/mgb4_core.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/media/pci/mgb4/mgb4_core.c b/drivers/media/pci/mgb4/mgb4_core.c
index 60498a5abebf..ab4f07e2e560 100644
--- a/drivers/media/pci/mgb4/mgb4_core.c
+++ b/drivers/media/pci/mgb4/mgb4_core.c
@@ -642,9 +642,6 @@ static void mgb4_remove(struct pci_dev *pdev)
 	struct mgb4_dev *mgbdev = pci_get_drvdata(pdev);
 	int i;
 
-#ifdef CONFIG_DEBUG_FS
-	debugfs_remove_recursive(mgbdev->debugfs);
-#endif
 #if IS_REACHABLE(CONFIG_HWMON)
 	hwmon_device_unregister(mgbdev->hwmon_dev);
 #endif
@@ -659,6 +656,10 @@ static void mgb4_remove(struct pci_dev *pdev)
 		if (mgbdev->vin[i])
 			mgb4_vin_free(mgbdev->vin[i]);
 
+#ifdef CONFIG_DEBUG_FS
+	debugfs_remove_recursive(mgbdev->debugfs);
+#endif
+
 	device_remove_groups(&mgbdev->pdev->dev, mgb4_pci_groups);
 	free_spi(mgbdev);
 	free_i2c(mgbdev);

base-commit: 8771b7f31b7fff91a998e6afdb60650d4bac59a5
-- 
2.44.0

Re: [PATCH] media: mgb4: Fix double debugfs remove

[Hans Verkuil]

Hi Martin,

On 21/05/2024 18:22, tumic@gpxsee.org wrote:
> From: Martin Tůma <martin.tuma@digiteqautomotive.com>
> 
> Fixes an error where debugfs_remove_recursive() is called first on a parent
> directory and then again on a child which causes a kernel panic.

I accepted this patch for v6.10, but I would appreciate it if you can
make an additional patch for v6.11 that removes the #ifdef CONFIG_DEBUG_FS
lines where possible.

Most debugfs functions have a dummy implementation when that define is not
set, so it would clean up the driver if these unnecessary #ifdefs are removed.

Regards,

	Hans

> 
> Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com>
> ---
>  drivers/media/pci/mgb4/mgb4_core.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/media/pci/mgb4/mgb4_core.c b/drivers/media/pci/mgb4/mgb4_core.c
> index 60498a5abebf..ab4f07e2e560 100644
> --- a/drivers/media/pci/mgb4/mgb4_core.c
> +++ b/drivers/media/pci/mgb4/mgb4_core.c
> @@ -642,9 +642,6 @@ static void mgb4_remove(struct pci_dev *pdev)
>  	struct mgb4_dev *mgbdev = pci_get_drvdata(pdev);
>  	int i;
>  
> -#ifdef CONFIG_DEBUG_FS
> -	debugfs_remove_recursive(mgbdev->debugfs);
> -#endif
>  #if IS_REACHABLE(CONFIG_HWMON)
>  	hwmon_device_unregister(mgbdev->hwmon_dev);
>  #endif
> @@ -659,6 +656,10 @@ static void mgb4_remove(struct pci_dev *pdev)
>  		if (mgbdev->vin[i])
>  			mgb4_vin_free(mgbdev->vin[i]);
>  
> +#ifdef CONFIG_DEBUG_FS
> +	debugfs_remove_recursive(mgbdev->debugfs);
> +#endif
> +
>  	device_remove_groups(&mgbdev->pdev->dev, mgb4_pci_groups);
>  	free_spi(mgbdev);
>  	free_i2c(mgbdev);
> 
> base-commit: 8771b7f31b7fff91a998e6afdb60650d4bac59a5

Re: [PATCH] media: mgb4: Fix double debugfs remove

[Martin Tůma]

On 27. 05. 24 9:36 dop., Hans Verkuil wrote:
> Hi Martin,
> 
> On 21/05/2024 18:22, tumic@gpxsee.org wrote:
>> From: Martin Tůma <martin.tuma@digiteqautomotive.com>
>>
>> Fixes an error where debugfs_remove_recursive() is called first on a parent
>> directory and then again on a child which causes a kernel panic.
> 
> I accepted this patch for v6.10, but I would appreciate it if you can
> make an additional patch for v6.11 that removes the #ifdef CONFIG_DEBUG_FS
> lines where possible.
> 
> Most debugfs functions have a dummy implementation when that define is not
> set, so it would clean up the driver if these unnecessary #ifdefs are removed.
> 

Ok, I will do it and send the patch in the next days.

M.

> Regards,
> 
> 	Hans
> 
>>
>> Signed-off-by: Martin Tůma <martin.tuma@digiteqautomotive.com>
>> ---
>>   drivers/media/pci/mgb4/mgb4_core.c | 7 ++++---
>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/pci/mgb4/mgb4_core.c b/drivers/media/pci/mgb4/mgb4_core.c
>> index 60498a5abebf..ab4f07e2e560 100644
>> --- a/drivers/media/pci/mgb4/mgb4_core.c
>> +++ b/drivers/media/pci/mgb4/mgb4_core.c
>> @@ -642,9 +642,6 @@ static void mgb4_remove(struct pci_dev *pdev)
>>   	struct mgb4_dev *mgbdev = pci_get_drvdata(pdev);
>>   	int i;
>>   
>> -#ifdef CONFIG_DEBUG_FS
>> -	debugfs_remove_recursive(mgbdev->debugfs);
>> -#endif
>>   #if IS_REACHABLE(CONFIG_HWMON)
>>   	hwmon_device_unregister(mgbdev->hwmon_dev);
>>   #endif
>> @@ -659,6 +656,10 @@ static void mgb4_remove(struct pci_dev *pdev)
>>   		if (mgbdev->vin[i])
>>   			mgb4_vin_free(mgbdev->vin[i]);
>>   
>> +#ifdef CONFIG_DEBUG_FS
>> +	debugfs_remove_recursive(mgbdev->debugfs);
>> +#endif
>> +
>>   	device_remove_groups(&mgbdev->pdev->dev, mgb4_pci_groups);
>>   	free_spi(mgbdev);
>>   	free_i2c(mgbdev);
>>
>> base-commit: 8771b7f31b7fff91a998e6afdb60650d4bac59a5
> 
>