Cycles: Try to avoid infinite loops by catching invalid ray states

intern/cycles/device/device.h

@@ -228,6 +228,14 @@ public:
 	DeviceInfo info;
 	virtual const string& error_message() { return error_msg; }
 	bool have_error() { return !error_message().empty(); }
+	virtual void set_error(const string& error)
+	{
+		if(!have_error()) {
+			error_msg = error;
+		}
+		fprintf(stderr, "%s\n", error.c_str());
+		fflush(stderr);
+	}
 	virtual bool show_samples() const { return false; }
 
 	/* statistics */

intern/cycles/device/device_split_kernel.cpp

@@ -205,6 +205,7 @@ bool DeviceSplitKernel::path_trace(DeviceTask *task,
 		 */
 		device->mem_zero(work_pool_wgs);
 		device->mem_zero(split_data);
+		device->mem_zero(ray_state);
 
 		if(!enqueue_split_kernel_data_init(KernelDimensions(global_size, local_size),
 		                                   subtile,
@@ -254,7 +255,15 @@ bool DeviceSplitKernel::path_trace(DeviceTask *task,
 			activeRaysAvailable = false;
 
 			for(int rayStateIter = 0; rayStateIter < global_size[0] * global_size[1]; ++rayStateIter) {
-				if(int8_t(ray_state.get_data()[rayStateIter]) != RAY_INACTIVE) {
+				int8_t state = ray_state.get_data()[rayStateIter];
+
+				if(state != RAY_INACTIVE) {
+					if(state == RAY_INVALID) {
+						/* Something went wrong, abort to avoid looping endlessly. */
+						device->set_error("Split kernel error: invalid ray state");
+						return false;
+					}
+
 					/* Not all rays are RAY_INACTIVE. */
 					activeRaysAvailable = true;
 					break;

intern/cycles/kernel/kernel_types.h

@@ -1297,20 +1297,19 @@ enum QueueNumber {
 #define RAY_STATE_MASK 0x007
 #define RAY_FLAG_MASK 0x0F8
 enum RayState {
+	RAY_INVALID = 0,
 	/* Denotes ray is actively involved in path-iteration. */
-	RAY_ACTIVE = 0,
+	RAY_ACTIVE,
 	/* Denotes ray has completed processing all samples and is inactive. */
-	RAY_INACTIVE = 1,
+	RAY_INACTIVE,
 	/* Denoted ray has exited path-iteration and needs to update output buffer. */
-	RAY_UPDATE_BUFFER = 2,
+	RAY_UPDATE_BUFFER,
 	/* Donotes ray has hit background */
-	RAY_HIT_BACKGROUND = 3,
+	RAY_HIT_BACKGROUND,
 	/* Denotes ray has to be regenerated */
-	RAY_TO_REGENERATE = 4,
+	RAY_TO_REGENERATE,
 	/* Denotes ray has been regenerated */
-	RAY_REGENERATED = 5,
-	/* Denotes ray should skip direct lighting */
-	RAY_SKIP_DL = 6,
+	RAY_REGENERATED,
 	/* Flag's ray has to execute shadow blocked function in AO part */
 	RAY_SHADOW_RAY_CAST_AO = 16,
 	/* Flag's ray has to execute shadow blocked function in direct lighting part. */