[PATCH] drm/amdgpu: Fix the page fault issue in amdgpu_irq_fini

[Christian König]

Am 18.03.21 um 12:48 schrieb Emily Deng:
> For some source, it will be shared by some client ID and source ID.
> To fix the page fault issue, set all those to null.
>
> Signed-off-by: Emily Deng <Emily.Deng at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c | 16 +++++++++++++---
>   1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
> index af026109421a..623b1ac6231d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_irq.c
> @@ -359,7 +359,7 @@ int amdgpu_irq_init(struct amdgpu_device *adev)
>    */
>   void amdgpu_irq_fini(struct amdgpu_device *adev)
>   {
> -	unsigned i, j;
> +	unsigned i, j, m, n;
>   
>   	if (adev->irq.installed) {
>   		drm_irq_uninstall(adev_to_drm(adev));
> @@ -380,12 +380,22 @@ void amdgpu_irq_fini(struct amdgpu_device *adev)
>   			if (!src)
>   				continue;
>   
> -			kfree(src->enabled_types);
> +			if (src->enabled_types)
> +				kfree(src->enabled_types);

A NULL check before kfree() is unecessary and will be complained about 
by the static checkers.

> +
>   			src->enabled_types = NULL;
> +

Unrelated white space change.

>   			if (src->data) {
>   				kfree(src->data);
>   				kfree(src);
> -				adev->irq.client[i].sources[j] = NULL;
> +			}
> +
> +			for (m = 0; m < AMDGPU_IRQ_CLIENTID_MAX; ++m) {
> +				if (!adev->irq.client[m].sources)
> +					continue;
> +				for (n = 0; n < AMDGPU_MAX_IRQ_SRC_ID; ++n)
> +					if (adev->irq.client[m].sources[n] == src)
> +						adev->irq.client[m].sources[n] = NULL;

Hui what? The memory you set to NULL here is freed on the line below.

Accessing it after that would be illegal, so why do you want to set it 
to NULL?

Christian.

>   			}
>   		}
>   		kfree(adev->irq.client[i].sources);