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
kunit_try_catch_throw(struct kunit_try_catch * try_catch)18 void __noreturn kunit_try_catch_throw(struct kunit_try_catch *try_catch)
19 {
20 try_catch->try_result = -EFAULT;
21 kthread_complete_and_exit(try_catch->try_completion, -EFAULT);
22 }
23 EXPORT_SYMBOL_GPL(kunit_try_catch_throw);
24
kunit_generic_run_threadfn_adapter(void * data)25 static int kunit_generic_run_threadfn_adapter(void *data)
26 {
27 struct kunit_try_catch *try_catch = data;
28
29 try_catch->try(try_catch->context);
30
31 kthread_complete_and_exit(try_catch->try_completion, 0);
32 }
33
kunit_test_timeout(void)34 static unsigned long kunit_test_timeout(void)
35 {
36 /*
37 * TODO(brendanhiggins@google.com): We should probably have some type of
38 * variable timeout here. The only question is what that timeout value
39 * should be.
40 *
41 * The intention has always been, at some point, to be able to label
42 * tests with some type of size bucket (unit/small, integration/medium,
43 * large/system/end-to-end, etc), where each size bucket would get a
44 * default timeout value kind of like what Bazel does:
45 * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size
46 * There is still some debate to be had on exactly how we do this. (For
47 * one, we probably want to have some sort of test runner level
48 * timeout.)
49 *
50 * For more background on this topic, see:
51 * https://mike-bland.com/2011/11/01/small-medium-large.html
52 *
53 * If tests timeout due to exceeding sysctl_hung_task_timeout_secs,
54 * the task will be killed and an oops generated.
55 */
56 return 300 * msecs_to_jiffies(MSEC_PER_SEC); /* 5 min */
57 }
58
kunit_try_catch_run(struct kunit_try_catch * try_catch,void * context)59 void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
60 {
61 DECLARE_COMPLETION_ONSTACK(try_completion);
62 struct kunit *test = try_catch->test;
63 struct task_struct *task_struct;
64 int exit_code, time_remaining;
65
66 try_catch->context = context;
67 try_catch->try_completion = &try_completion;
68 try_catch->try_result = 0;
69 task_struct = kthread_create(kunit_generic_run_threadfn_adapter,
70 try_catch, "kunit_try_catch_thread");
71 if (IS_ERR(task_struct)) {
72 try_catch->catch(try_catch->context);
73 return;
74 }
75 get_task_struct(task_struct);
76 wake_up_process(task_struct);
77
78 time_remaining = wait_for_completion_timeout(&try_completion,
79 kunit_test_timeout());
80 if (time_remaining == 0) {
81 kunit_err(test, "try timed out\n");
82 try_catch->try_result = -ETIMEDOUT;
83 kthread_stop(task_struct);
84 }
85
86 put_task_struct(task_struct);
87 exit_code = try_catch->try_result;
88
89 if (!exit_code)
90 return;
91
92 if (exit_code == -EFAULT)
93 try_catch->try_result = 0;
94 else if (exit_code == -EINTR)
95 kunit_err(test, "wake_up_process() was never called\n");
96 else if (exit_code)
97 kunit_err(test, "Unknown error: %d\n", exit_code);
98
99 try_catch->catch(try_catch->context);
100 }
101 EXPORT_SYMBOL_GPL(kunit_try_catch_run);
102