The plane state in __drm_gem_reset_shadow_plane) can be NULL. Do not deref that pointer, but forward NULL to the other plane-reset helpers. Clears plane->state to NULL.

Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Fixes: b71565022031 ("drm/gem: Export implementation of shadow-plane helpers") Reported-by: Dan Carpenter dan.carpenter@linaro.org Closes: https://lore.kernel.org/dri-devel/aPIDAsHIUHp_qSW4@stanley.mountain/ Cc: Thomas Zimmermann tzimmermann@suse.de Cc: Melissa Wen melissa.srw@gmail.com Cc: Maarten Lankhorst maarten.lankhorst@linux.intel.com Cc: Maxime Ripard mripard@kernel.org Cc: David Airlie airlied@gmail.com Cc: Simona Vetter simona@ffwll.ch Cc: dri-devel@lists.freedesktop.org Cc: stable@vger.kernel.org # v5.15+ --- drivers/gpu/drm/drm_gem_atomic_helper.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_atomic_helper.c b/drivers/gpu/drm/drm_gem_atomic_helper.c index ebf305fb24f0..6fb55601252f 100644 --- a/drivers/gpu/drm/drm_gem_atomic_helper.c +++ b/drivers/gpu/drm/drm_gem_atomic_helper.c @@ -310,8 +310,12 @@ EXPORT_SYMBOL(drm_gem_destroy_shadow_plane_state); void __drm_gem_reset_shadow_plane(struct drm_plane *plane, struct drm_shadow_plane_state *shadow_plane_state) { - __drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base); - drm_format_conv_state_init(&shadow_plane_state->fmtcnv_state); + if (shadow_plane_state) { + __drm_atomic_helper_plane_reset(plane, &shadow_plane_state->base); + drm_format_conv_state_init(&shadow_plane_state->fmtcnv_state); + } else { + __drm_atomic_helper_plane_reset(plane, NULL); + } } EXPORT_SYMBOL(__drm_gem_reset_shadow_plane);