// 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;} 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, try_catch->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);