Re: [PATCH] drm/gem: Fix a GEM leak in drm_gem_get_unmapped_area()

[Boris Brezillon <boris.brezillon@collabora.com>]

On Tue,  6 Jan 2026 17:49:35 +0100
Boris Brezillon <boris.brezillon@collabora.com> wrote:

> drm_gem_object_lookup_at_offset() can return a valid object with
> filp or filp->f_op->get_unmapped_area set to NULL. Make sure we still
> release the ref we acquired on such objects.
> 
> Cc: Loïc Molinari <loic.molinari@collabora.com>
> Fixes: 99bda20d6d4c ("drm/gem: Introduce drm_gem_get_unmapped_area() fop")
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>

Queued to drm-misc-next.

> ---
>  drivers/gpu/drm/drm_gem.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 36c8af123877..f7cbf6e8d1e0 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -1298,11 +1298,13 @@ unsigned long drm_gem_get_unmapped_area(struct file *filp, unsigned long uaddr,
>  	unsigned long ret;
>  
>  	obj = drm_gem_object_lookup_at_offset(filp, pgoff, len >> PAGE_SHIFT);
> -	if (IS_ERR(obj) || !obj->filp || !obj->filp->f_op->get_unmapped_area)
> -		return mm_get_unmapped_area(filp, uaddr, len, 0, flags);
> +	if (IS_ERR(obj))
> +		obj = NULL;
>  
> -	ret = obj->filp->f_op->get_unmapped_area(obj->filp, uaddr, len, 0,
> -						 flags);
> +	if (!obj || !obj->filp || !obj->filp->f_op->get_unmapped_area)
> +		ret = mm_get_unmapped_area(filp, uaddr, len, 0, flags);
> +	else
> +		ret = obj->filp->f_op->get_unmapped_area(obj->filp, uaddr, len, 0, flags);
>  
>  	drm_gem_object_put(obj);
>