Re: [PATCH] drm/xe: Fix ref counting leak on page fault

[Mika Kuoppala <mika.kuoppala@linux.intel.com>]

Matthew Brost <matthew.brost@intel.com> writes:

> If a page fault occurs on VM not in fault a ref can be leaked. Fix this.
>
> Fixes: dd08ebf6c352 ("drm/xe: Introduce a new DRM driver for Intel GPUs")
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>

Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>

> ---
>  drivers/gpu/drm/xe/xe_gt_pagefault.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_gt_pagefault.c b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> index c26e4fcca01e..73c535193a98 100644
> --- a/drivers/gpu/drm/xe/xe_gt_pagefault.c
> +++ b/drivers/gpu/drm/xe/xe_gt_pagefault.c
> @@ -146,10 +146,12 @@ static int handle_pagefault(struct xe_gt *gt, struct pagefault *pf)
>  	/* ASID to VM */
>  	mutex_lock(&xe->usm.lock);
>  	vm = xa_load(&xe->usm.asid_to_vm, pf->asid);
> -	if (vm)
> +	if (vm && xe_vm_in_fault_mode(vm))
>  		xe_vm_get(vm);
> +	else
> +		vm = NULL;
>  	mutex_unlock(&xe->usm.lock);
> -	if (!vm || !xe_vm_in_fault_mode(vm))
> +	if (!vm)
>  		return -EINVAL;
>  
>  retry_userptr:
> -- 
> 2.34.1