Fix #33125: cycles OSL crash with multiple render sessions running at the same time.

intern/cycles/kernel/osl/osl_globals.h

@@ -68,6 +68,11 @@ struct OSLGlobals {
 	};
 
 	static tls_ptr(ThreadData, thread_data);
+	static thread_mutex thread_data_mutex;
+	static volatile int thread_data_users;
+
+	void thread_data_init();
+	void thread_data_free();
 };
 
 CCL_NAMESPACE_END

intern/cycles/kernel/osl/osl_shader.cpp

@@ -32,9 +32,32 @@
 CCL_NAMESPACE_BEGIN
 
 tls_ptr(OSLGlobals::ThreadData, OSLGlobals::thread_data);
+volatile int OSLGlobals::thread_data_users = 0;
+thread_mutex OSLGlobals::thread_data_mutex;
 
 /* Threads */
 
+void OSLGlobals::thread_data_init()
+{
+	thread_scoped_lock thread_data_lock(thread_data_mutex);
+
+	if(thread_data_users == 0)
+		tls_create(OSLGlobals::ThreadData, thread_data);
+
+	thread_data_users++;
+}
+
+void OSLGlobals::thread_data_free()
+{
+	/* thread local storage delete */
+	thread_scoped_lock thread_data_lock(thread_data_mutex);
+
+	thread_data_users--;
+
+	if(thread_data_users == 0)
+		tls_delete(OSLGlobals::ThreadData, thread_data);
+}
+
 void OSLShader::thread_init(KernelGlobals *kg)
 {
 	OSL::ShadingSystem *ss = kg->osl.ss;

intern/cycles/render/osl.cpp

@@ -45,6 +45,8 @@ CCL_NAMESPACE_BEGIN
 
 OSLShaderManager::OSLShaderManager()
 {
+	thread_data_initialized = false;
+
 	services = new OSLRenderServices();
 
 	shading_system_init();
@@ -91,8 +93,6 @@ void OSLShaderManager::device_update(Device *device, DeviceScene *dscene, Scene
 	og->background_state = og->surface_state[background_id & SHADER_MASK];
 	og->use = true;
 
-	tls_create(OSLGlobals::ThreadData, og->thread_data);
-
 	foreach(Shader *shader, scene->shaders)
 		shader->need_update = false;
 
@@ -102,6 +102,11 @@ void OSLShaderManager::device_update(Device *device, DeviceScene *dscene, Scene
 	scene->image_manager->set_osl_texture_system((void*)ts);
 
 	device_update_common(device, dscene, scene, progress);
+
+	if(!thread_data_initialized) {
+		og->thread_data_init();
+		thread_data_initialized = true;
+	}
 }
 
 void OSLShaderManager::device_free(Device *device, DeviceScene *dscene)
@@ -114,12 +119,15 @@ void OSLShaderManager::device_free(Device *device, DeviceScene *dscene)
 	og->use = false;
 	og->ss = NULL;
 
-	tls_delete(OSLGlobals::ThreadData, og->thread_data);
-
 	og->surface_state.clear();
 	og->volume_state.clear();
 	og->displacement_state.clear();
 	og->background_state.reset();
+
+	if(thread_data_initialized) {
+		og->thread_data_free();
+		thread_data_initialized = false;
+	}
 }
 
 void OSLShaderManager::texture_system_init()

intern/cycles/render/osl.h

@@ -73,6 +73,8 @@ protected:
 	OSLRenderServices *services;
 	OSL::ErrorHandler errhandler;
 	set<string> loaded_shaders;
+
+	bool thread_data_initialized;
 };
 
 #endif