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 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(try_catch->context);
  30
  31         complete_and_exit(try_catch->try_completion, 0);
  32 }
  33
  34 static unsigned long kunit_test_timeout(void)
  35 {
  36         unsigned long timeout_msecs;
  37
  38         /*
  39          * TODO(brendanhiggins@google.com): We should probably have some type of
  40          * variable timeout here. The only question is what that timeout value
  41          * should be.
  42          *
  43          * The intention has always been, at some point, to be able to label
  44          * tests with some type of size bucket (unit/small, integration/medium,
  45          * large/system/end-to-end, etc), where each size bucket would get a
  46          * default timeout value kind of like what Bazel does:
  47          * https://docs.bazel.build/versions/master/be/common-definitions.html#test.size
  48          * There is still some debate to be had on exactly how we do this. (For
  49          * one, we probably want to have some sort of test runner level
  50          * timeout.)
  51          *
  52          * For more background on this topic, see:
  53          * https://mike-bland.com/2011/11/01/small-medium-large.html
  54          */
  55         if (sysctl_hung_task_timeout_secs) {
  56                 /*
  57                  * If sysctl_hung_task is active, just set the timeout to some
  58                  * value less than that.
  59                  *
  60                  * In regards to the above TODO, if we decide on variable
  61                  * timeouts, this logic will likely need to change.
  62                  */
  63                 timeout_msecs = (sysctl_hung_task_timeout_secs - 1) *
  64                                 MSEC_PER_SEC;
  65         } else {
  66                 timeout_msecs = 300 * MSEC_PER_SEC; /* 5 min */
  67         }
  68
  69         return timeout_msecs;
  70 }
  71
  72 void kunit_try_catch_run(struct kunit_try_catch *try_catch, void *context)
  73 {
  74         DECLARE_COMPLETION_ONSTACK(try_completion);
  75         struct kunit *test = try_catch->test;
  76         struct task_struct *task_struct;
  77         int exit_code, time_remaining;
  78
  79         try_catch->context = context;
  80         try_catch->try_completion = &try_completion;
  81         try_catch->try_result = 0;
  82         task_struct = kthread_run(kunit_generic_run_threadfn_adapter,
  83                                   try_catch,
  84                                   "kunit_try_catch_thread");
  85         if (IS_ERR(task_struct)) {
  86                 try_catch->catch(try_catch->context);
  87                 return;
  88         }
  89
  90         time_remaining = wait_for_completion_timeout(&try_completion,
  91                                                      kunit_test_timeout());
  92         if (time_remaining == 0) {
  93                 kunit_err(test, "try timed out\n");
  94                 try_catch->try_result = -ETIMEDOUT;
  95         }
  96
  97         exit_code = try_catch->try_result;
  98
  99         if (!exit_code)
 100                 return;
 101
 102         if (exit_code == -EFAULT)
 103                 try_catch->try_result = 0;
 104         else if (exit_code == -EINTR)
 105                 kunit_err(test, "wake_up_process() was never called\n");
 106         else if (exit_code)
 107                 kunit_err(test, "Unknown error: %d\n", exit_code);
 108
 109         try_catch->catch(try_catch->context);
 110 }
 111 EXPORT_SYMBOL_GPL(kunit_try_catch_run);