On 02/22/2018 08:09 AM, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
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@xxxxxxxx>
Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
---
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;
Daniel, I have put your R-b tag, but I had removed suggested
"WARN_ON(crtc_state && crtc_state->enable);"
here as it fires each time when crtc_state is not NULL.
Please let me know if this is not ok and you want me to remove
your R-b tag.
+ return 0;
+
+ drm_mode_get_hv_timing(&crtc_state->mode, &clip.x2, &clip.y2);
if (!pipe->funcs || !pipe->funcs->check)
return 0;
Thank you,
Oleksandr
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