lib/kunit/try-catch.c

   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/sysctl.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         complete_and_exit(try_catch->try_completion, -EFAULT);
  22 }
  23
  24 static int kunit_generic_run_threadfn_adapter(void *data)
  25 {
  26         struct kunit_try_catch *try_catch = data;
  27
  28         try_catch->try(try_catch->context);
  29
  30         complete_and_exit(try_catch->try_completion, 0);
  31 }
  32
  33 static unsigned long kunit_test_timeout(void)
  34 {
  35         unsigned long timeout_msecs;
  36
  37         /*
  38          * TODO(brendanhiggins@google.com): We should probably have some type of
  39          * variable timeout here. The only question is what that timeout value
  40          * should be.
  41          *
  42          * The intention has always been, at some point, to be able to label
  43          * tests with some type of size bucket (unit/small, integration/medium,
  44          * large/system/end-to-end, etc), where each size bucket would get a
  45          * default timeout value kind of like what Bazel does:
  46          * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size
  47          * There is still some debate to be had on exactly how we do this. (For
  48          * one, we probably want to have some sort of test runner level
  49          * timeout.)
  50          *
  51          * For more background on this topic, see:
  52          * https://mike-bland.com/2011/11/01/small-medium-large.html
  53          */
  54         if (sysctl_hung_task_timeout_secs) {
  55                 /*
  56                  * If sysctl_hung_task is active, just set the timeout to some
  57                  * value less than that.
  58                  *
  59                  * In regards to the above TODO, if we decide on variable
  60                  * timeouts, this logic will likely need to change.
  61                  */
  62                 timeout_msecs = (sysctl_hung_task_timeout_secs - 1) *
  63                                 MSEC_PER_SEC;
  64         } else {
  65                 timeout_msecs = 300 * MSEC_PER_SEC; /* 5 min */
  66         }
  67
  68         return timeout_msecs;
  69 }
  70
  71 void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
  72 {
  73         DECLARE_COMPLETION_ONSTACK(try_completion);
  74         struct kunit *test = try_catch->test;
  75         struct task_struct *task_struct;
  76         int exit_code, time_remaining;
  77
  78         try_catch->context = context;
  79         try_catch->try_completion = &try_completion;
  80         try_catch->try_result = 0;
  81         task_struct = kthread_run(kunit_generic_run_threadfn_adapter,
  82                                   try_catch,
  83                                   "kunit_try_catch_thread");
  84         if (IS_ERR(task_struct)) {
  85                 try_catch->catch(try_catch->context);
  86                 return;
  87         }
  88
  89         time_remaining = wait_for_completion_timeout(&try_completion,
  90                                                      kunit_test_timeout());
  91         if (time_remaining == 0) {
  92                 kunit_err(test, "try timed out\n");
  93                 try_catch->try_result = -ETIMEDOUT;
  94         }
  95
  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                 kunit_err(test, "wake_up_process() was never called\n");
 105         else if (exit_code)
 106                 kunit_err(test, "Unknown error: %d\n", exit_code);
 107
 108         try_catch->catch(try_catch->context);
 109 }