linux-kernel - Re: [PATCH] media: mgb4: Fix double debugfs remove

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Message-ID: <2366ed1f-c6e0-40ce-90f3-e1a4b2d264bb@gpxsee.org>
Date: Mon, 27 May 2024 15:33:05 +0200
From: Martin Tůma <tumic@...see.org>
To: Hans Verkuil <hverkuil@...all.nl>,
 Mauro Carvalho Chehab <mchehab@...nel.org>
Cc: linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
 Martin Tůma <martin.tuma@...iteqautomotive.com>
Subject: Re: [PATCH] media: mgb4: Fix double debugfs remove

On 27. 05. 24 9:36 dop., Hans Verkuil wrote:
> Hi Martin,
> 
> On 21/05/2024 18:22, tumic@...see.org wrote:
>> From: Martin Tůma <martin.tuma@...iteqautomotive.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@...iteqautomotive.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
> 
>