Messages in this thread Patch in this message | | | From | Oleksandr Andrushchenko <> | Subject | [PATCH v1] drm/simple_kms_helper: Fix NULL pointer dereference with no active CRTC | Date | Thu, 22 Feb 2018 08:09:19 +0200 |
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From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
It is possible that drm_simple_kms_plane_atomic_check called with no CRTC set, e.g. when user-space application sets CRTC_ID/FB_ID to 0 before doing any actual drawing. This leads to NULL pointer dereference because in this case new CRTC state is NULL and must be checked before accessing.
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
--- Changes since initial: - re-worked checks for null CRTC as suggested by Daniel Vetter --- drivers/gpu/drm/drm_simple_kms_helper.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c index 9ca8a4a59b74..4a1dbd88b1ec 100644 --- a/drivers/gpu/drm/drm_simple_kms_helper.c +++ b/drivers/gpu/drm/drm_simple_kms_helper.c @@ -121,12 +121,6 @@ static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane, pipe = container_of(plane, struct drm_simple_display_pipe, plane); crtc_state = drm_atomic_get_new_crtc_state(plane_state->state, &pipe->crtc); - if (!crtc_state->enable) - return 0; /* nothing to check when disabling or disabled */ - - if (crtc_state->enable) - drm_mode_get_hv_timing(&crtc_state->mode, - &clip.x2, &clip.y2); ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state, &clip, @@ -137,7 +131,9 @@ static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane, return ret; if (!plane_state->visible) - return -EINVAL; + return 0; + + drm_mode_get_hv_timing(&crtc_state->mode, &clip.x2, &clip.y2); if (!pipe->funcs || !pipe->funcs->check) return 0; -- 2.7.4
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