[PATCH v5 4/9] drm/vc4: hdmi: Don't access the connector state in reset if kmalloc fails

Maxime Ripard
2020-12-07T15:59:36Z

drm_atomic_helper_connector_reset uses kmalloc which, from an API
standpoint, can fail, and thus setting connector->state to NULL.
However, our reset hook then calls drm_atomic_helper_connector_tv_reset
that will access connector->state without checking if it's a valid
pointer or not.

Make sure we don't end up accessing a NULL pointer.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Suggested-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
---
drivers/gpu/drm/vc4/vc4_hdmi.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/vc4/vc4_hdmi.c b/drivers/gpu/drm/vc4/vc4_hdmi.c
index a88aa20beeb6..61039cc89d9d 100644
--- a/drivers/gpu/drm/vc4/vc4_hdmi.c
+++ b/drivers/gpu/drm/vc4/vc4_hdmi.c
@@ -171,7 +171,9 @@ static int vc4_hdmi_connector_get_modes(struct drm_connector *connector)
static void vc4_hdmi_connector_reset(struct drm_connector *connector)
{
drm_atomic_helper_connector_reset(connector);
- drm_atomic_helper_connector_tv_reset(connector);
+
+ if (connector->state)
+ drm_atomic_helper_connector_tv_reset(connector);
}

static const struct drm_connector_funcs vc4_hdmi_connector_funcs = {
--
2.28.0