// SPDX-License-Identifier: GPL-2.0/* * An API to allow a function, that may fail, to be executed, and recover in a * controlled manner. * * Copyright (C) 2019, Google LLC. * Author: Brendan Higgins <brendanhiggins@google.com> */ #include <kunit/test.h>#include <linux/completion.h>#include <linux/kernel.h>#include <linux/kthread.h>#include <linux/sched/task.h> #include "try-catch-impl.h" void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch){	try_catch->try_result = -EFAULT;	kthread_exit(0);}EXPORT_SYMBOL_GPL(kunit_try_catch_throw); static int kunit_generic_run_threadfn_adapter(void *data){	struct kunit_try_catch *try_catch = data; 	try_catch->try_result = -EINTR;	try_catch->try(try_catch->context);	if (try_catch->try_result == -EINTR)		try_catch->try_result = 0; 	return 0;} static unsigned long kunit_test_timeout(void){	/*	 * TODO(brendanhiggins@google.com): We should probably have some type of	 * variable timeout here. The only question is what that timeout value	 * should be.	 *	 * The intention has always been, at some point, to be able to label	 * tests with some type of size bucket (unit/small, integration/medium,	 * large/system/end-to-end, etc), where each size bucket would get a	 * default timeout value kind of like what Bazel does:	 * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size	 * There is still some debate to be had on exactly how we do this. (For	 * one, we probably want to have some sort of test runner level	 * timeout.)	 *	 * For more background on this topic, see:	 * https://mike-bland.com/2011/11/01/small-medium-large.html	 *	 * If tests timeout due to exceeding sysctl_hung_task_timeout_secs,	 * the task will be killed and an oops generated.	 */	return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */} void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context){	struct kunit *test = try_catch->test;	struct task_struct *task_struct;	struct completion *task_done;	int exit_code, time_remaining; 	try_catch->context = context;	try_catch->try_result = 0;	task_struct = kthread_create(kunit_generic_run_threadfn_adapter,				     try_catch, "kunit_try_catch_thread");	if (IS_ERR(task_struct)) {		try_catch->try_result = PTR_ERR(task_struct);		try_catch->catch(try_catch->context);		return;	}	get_task_struct(task_struct);	/*	 * As for a vfork(2), task_struct->vfork_done (pointing to the	 * underlying kthread->exited) can be used to wait for the end of a	 * kernel thread. It is set to NULL when the thread exits, so we	 * keep a copy here.	 */	task_done = task_struct->vfork_done;	wake_up_process(task_struct); 	time_remaining = wait_for_completion_timeout(task_done,						     kunit_test_timeout());	if (time_remaining == 0) {		try_catch->try_result = -ETIMEDOUT;		kthread_stop(task_struct);	} 	put_task_struct(task_struct);	exit_code = try_catch->try_result; 	if (!exit_code)		return; 	if (exit_code == -EFAULT)		try_catch->try_result = 0;	else if (exit_code == -EINTR) {		if (test->last_seen.file)			kunit_err(test, "try faulted: last line seen %s:%d\n",				  test->last_seen.file, test->last_seen.line);		else			kunit_err(test, "try faulted\n");	} else if (exit_code == -ETIMEDOUT)		kunit_err(test, "try timed out\n");	else if (exit_code)		kunit_err(test, "Unknown error: %d\n", exit_code); 	try_catch->catch(try_catch->context);}EXPORT_SYMBOL_GPL(kunit_try_catch_run);