Re: [Intel-gfx] [PATCH] i915: fix memory leak with using debugfs_lookup()

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Thu, Feb 02, 2023 at 03:13:09PM +0100, Greg Kroah-Hartman wrote:
> When calling debugfs_lookup() the result must have dput() called on it,
> otherwise the memory will leak over time.  To make things simpler, just
> call debugfs_lookup_and_remove() instead which handles all of the logic
> at once.
> 
> Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
> Cc: Zhi Wang <zhi.a.wang@intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: David Airlie <airlied@gmail.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: intel-gvt-dev@lists.freedesktop.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

Zhenyu or Zhi, could you please propagate this through your gvt branch?

> ---
>  drivers/gpu/drm/i915/gvt/kvmgt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
> index 8ae7039b3683..de675d799c7d 100644
> --- a/drivers/gpu/drm/i915/gvt/kvmgt.c
> +++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
> @@ -699,7 +699,7 @@ static void intel_vgpu_close_device(struct vfio_device *vfio_dev)
>  
>  	clear_bit(INTEL_VGPU_STATUS_ATTACHED, vgpu->status);
>  
> -	debugfs_remove(debugfs_lookup(KVMGT_DEBUGFS_FILENAME, vgpu->debugfs));
> +	debugfs_lookup_and_remove(KVMGT_DEBUGFS_FILENAME, vgpu->debugfs);
>  
>  	kvm_page_track_unregister_notifier(vgpu->vfio_device.kvm,
>  					   &vgpu->track_node);
> -- 
> 2.39.1
>