[PATCH] drm/i915: check before removing mm notifier

[Nirmoy Das]

Merged it to drm-intel-gt-next with s/check/Check

On 2/19/2024 1:50 PM, Nirmoy Das wrote:
> Error in mmu_interval_notifier_insert() can leave a NULL
> notifier.mm pointer. Catch that and return early.
>
> Cc: Andi Shyti <andi.shyti at linux.intel.com>
> Cc: Shawn Lee <shawn.c.lee at intel.com>
> Signed-off-by: Nirmoy Das <nirmoy.das at intel.com>
> ---
>   drivers/gpu/drm/i915/gem/i915_gem_userptr.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> index 0e21ce9d3e5a..61abfb505766 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_userptr.c
> @@ -349,6 +349,9 @@ i915_gem_userptr_release(struct drm_i915_gem_object *obj)
>   {
>   	GEM_WARN_ON(obj->userptr.page_ref);
>   
> +	if (!obj->userptr.notifier.mm)
> +		return;
> +
>   	mmu_interval_notifier_remove(&obj->userptr.notifier);
>   	obj->userptr.notifier.mm = NULL;
>   }