1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * An API to allow a function, that may fail, to be executed, and recover in a 4 * controlled manner. 5 * 6 * Copyright (C) 2019, Google LLC. 7 * Author: Brendan Higgins <brendanhiggins@google.com> 8 */ 9 10 #include <kunit/test.h> 11 #include <linux/completion.h> 12 #include <linux/kernel.h> 13 #include <linux/kthread.h> 14 #include <linux/sched/task.h> 15 16 #include "try-catch-impl.h" 17 18 void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch) 19 { 20 try_catch->try_result = -EFAULT; 21 kthread_exit(0); 22 } 23 EXPORT_SYMBOL_GPL(kunit_try_catch_throw); 24 25 static int kunit_generic_run_threadfn_adapter(void *data) 26 { 27 struct kunit_try_catch *try_catch = data; 28 29 try_catch->try_result = -EINTR; 30 try_catch->try(try_catch->context); 31 if (try_catch->try_result == -EINTR) 32 try_catch->try_result = 0; 33 34 return 0; 35 } 36 37 static unsigned long kunit_test_timeout(void) 38 { 39 /* 40 * TODO(brendanhiggins@google.com): We should probably have some type of 41 * variable timeout here. The only question is what that timeout value 42 * should be. 43 * 44 * The intention has always been, at some point, to be able to label 45 * tests with some type of size bucket (unit/small, integration/medium, 46 * large/system/end-to-end, etc), where each size bucket would get a 47 * default timeout value kind of like what Bazel does: 48 * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size 49 * There is still some debate to be had on exactly how we do this. (For 50 * one, we probably want to have some sort of test runner level 51 * timeout.) 52 * 53 * For more background on this topic, see: 54 * https://mike-bland.com/2011/11/01/small-medium-large.html 55 * 56 * If tests timeout due to exceeding sysctl_hung_task_timeout_secs, 57 * the task will be killed and an oops generated. 58 */ 59 return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */ 60 } 61 62 void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context) 63 { 64 struct kunit *test = try_catch->test; 65 struct task_struct *task_struct; 66 struct completion *task_done; 67 int exit_code, time_remaining; 68 69 try_catch->context = context; 70 try_catch->try_result = 0; 71 task_struct = kthread_create(kunit_generic_run_threadfn_adapter, 72 try_catch, "kunit_try_catch_thread"); 73 if (IS_ERR(task_struct)) { 74 try_catch->try_result = PTR_ERR(task_struct); 75 try_catch->catch(try_catch->context); 76 return; 77 } 78 get_task_struct(task_struct); 79 /* 80 * As for a vfork(2), task_struct->vfork_done (pointing to the 81 * underlying kthread->exited) can be used to wait for the end of a 82 * kernel thread. It is set to NULL when the thread exits, so we 83 * keep a copy here. 84 */ 85 task_done = task_struct->vfork_done; 86 wake_up_process(task_struct); 87 88 time_remaining = wait_for_completion_timeout(task_done, 89 kunit_test_timeout()); 90 if (time_remaining == 0) { 91 try_catch->try_result = -ETIMEDOUT; 92 kthread_stop(task_struct); 93 } 94 95 put_task_struct(task_struct); 96 exit_code = try_catch->try_result; 97 98 if (!exit_code) 99 return; 100 101 if (exit_code == -EFAULT) 102 try_catch->try_result = 0; 103 else if (exit_code == -EINTR) { 104 if (test->last_seen.file) 105 kunit_err(test, "try faulted: last line seen %s:%d\n", 106 test->last_seen.file, test->last_seen.line); 107 else 108 kunit_err(test, "try faulted\n"); 109 } else if (exit_code == -ETIMEDOUT) 110 kunit_err(test, "try timed out\n"); 111 else if (exit_code) 112 kunit_err(test, "Unknown error: %d\n", exit_code); 113 114 try_catch->catch(try_catch->context); 115 } 116 EXPORT_SYMBOL_GPL(kunit_try_catch_run); 117