From b18398c16e176513502f962b642f89225039ef1f Mon Sep 17 00:00:00 2001 From: Boris Brezillon Date: Tue, 7 Jan 2020 12:30:31 +0100 Subject: [PATCH] drm/bridge: Fix a NULL pointer dereference in drm_atomic_bridge_chain_check() drm_atomic_bridge_chain_check() callers can pass a NULL bridge. Let's bail out before dereferencing the bridge pointer when that happens. Reported-by: Chris Wilson Fixes: b86d895524ab ("drm/bridge: Add an ->atomic_check() hook") Signed-off-by: Boris Brezillon Reviewed-by: Laurent Pinchart Reviewed-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20200107113031.435604-1-boris.brezillon@collabora.com --- drivers/gpu/drm/drm_bridge.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index 37400607e9b7..32d43bfeeca1 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -938,15 +938,19 @@ int drm_atomic_bridge_chain_check(struct drm_bridge *bridge, struct drm_connector_state *conn_state) { struct drm_connector *conn = conn_state->connector; - struct drm_encoder *encoder = bridge->encoder; + struct drm_encoder *encoder; struct drm_bridge *iter; int ret; + if (!bridge) + return 0; + ret = drm_atomic_bridge_chain_select_bus_fmts(bridge, crtc_state, conn_state); if (ret) return ret; + encoder = bridge->encoder; list_for_each_entry_reverse(iter, &encoder->bridge_chain, chain_node) { int ret;