2024-05-21 16:32:32

by Martin Tůma

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

From: Martin Tůma <[email protected]>

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 <[email protected]>
---
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

2024-05-27 07:37:13

by Hans Verkuil

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

Hi Martin,

On 21/05/2024 18:22, [email protected] wrote:
> From: Martin Tůma <[email protected]>
>
> 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 <[email protected]>
> ---
> 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

2024-05-27 13:36:48

by Martin Tůma

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, [email protected] wrote:
>> From: Martin Tůma <[email protected]>
>>
>> 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 <[email protected]>
>> ---
>> 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
>
>