tools/testing/selftests/futex/functional/futex_requeue_pi_mismatched_ops.c

   1 /******************************************************************************
   2  *
   3  *   Copyright © International Business Machines  Corp., 2009
   4  *
   5  *   This program is free software;  you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation; either version 2 of the License, or
   8  *   (at your option) any later version.
   9  *
  10  * DESCRIPTION
  11  *      1. Block a thread using FUTEX_WAIT
  12  *      2. Attempt to use FUTEX_CMP_REQUEUE_PI on the futex from 1.
  13  *      3. The kernel must detect the mismatch and return -EINVAL.
  14  *
  15  * AUTHOR
  16  *      Darren Hart <dvhart@linux.intel.com>
  17  *
  18  * HISTORY
  19  *      2009-Nov-9: Initial version by Darren Hart <dvhart@linux.intel.com>
  20  *
  21  *****************************************************************************/
  22
  23 #include <errno.h>
  24 #include <getopt.h>
  25 #include <pthread.h>
  26 #include <stdio.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <time.h>
  30 #include "futextest.h"
  31 #include "logging.h"
  32
  33 #define TEST_NAME "futex-requeue-pi-mismatched-ops"
  34
  35 futex_t f1 = FUTEX_INITIALIZER;
  36 futex_t f2 = FUTEX_INITIALIZER;
  37 int child_ret = 0;
  38
  39 void usage(char *prog)
  40 {
  41         printf("Usage: %s\n", prog);
  42         printf("  -c    Use color\n");
  43         printf("  -h    Display this help message\n");
  44         printf("  -v L  Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
  45                VQUIET, VCRITICAL, VINFO);
  46 }
  47
  48 void *blocking_child(void *arg)
  49 {
  50         child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
  51         if (child_ret < 0) {
  52                 child_ret = -errno;
  53                 error("futex_wait\n", errno);
  54         }
  55         return (void *)&child_ret;
  56 }
  57
  58 int main(int argc, char *argv[])
  59 {
  60         int ret = RET_PASS;
  61         pthread_t child;
  62         int c;
  63
  64         while ((c = getopt(argc, argv, "chv:")) != -1) {
  65                 switch (c) {
  66                 case 'c':
  67                         log_color(1);
  68                         break;
  69                 case 'h':
  70                         usage(basename(argv[0]));
  71                         exit(0);
  72                 case 'v':
  73                         log_verbosity(atoi(optarg));
  74                         break;
  75                 default:
  76                         usage(basename(argv[0]));
  77                         exit(1);
  78                 }
  79         }
  80
  81         ksft_print_header();
  82         ksft_print_msg("%s: Detect mismatched requeue_pi operations\n",
  83                basename(argv[0]));
  84
  85         if (pthread_create(&child, NULL, blocking_child, NULL)) {
  86                 error("pthread_create\n", errno);
  87                 ret = RET_ERROR;
  88                 goto out;
  89         }
  90         /* Allow the child to block in the kernel. */
  91         sleep(1);
  92
  93         /*
  94          * The kernel should detect the waiter did not setup the
  95          * q->requeue_pi_key and return -EINVAL. If it does not,
  96          * it likely gave the lock to the child, which is now hung
  97          * in the kernel.
  98          */
  99         ret = futex_cmp_requeue_pi(&f1, f1, &f2, 1, 0, FUTEX_PRIVATE_FLAG);
 100         if (ret < 0) {
 101                 if (errno == EINVAL) {
 102                         /*
 103                          * The kernel correctly detected the mismatched
 104                          * requeue_pi target and aborted. Wake the child with
 105                          * FUTEX_WAKE.
 106                          */
 107                         ret = futex_wake(&f1, 1, FUTEX_PRIVATE_FLAG);
 108                         if (ret == 1) {
 109                                 ret = RET_PASS;
 110                         } else if (ret < 0) {
 111                                 error("futex_wake\n", errno);
 112                                 ret = RET_ERROR;
 113                         } else {
 114                                 error("futex_wake did not wake the child\n", 0);
 115                                 ret = RET_ERROR;
 116                         }
 117                 } else {
 118                         error("futex_cmp_requeue_pi\n", errno);
 119                         ret = RET_ERROR;
 120                 }
 121         } else if (ret > 0) {
 122                 fail("futex_cmp_requeue_pi failed to detect the mismatch\n");
 123                 ret = RET_FAIL;
 124         } else {
 125                 error("futex_cmp_requeue_pi found no waiters\n", 0);
 126                 ret = RET_ERROR;
 127         }
 128
 129         pthread_join(child, NULL);
 130
 131         if (!ret)
 132                 ret = child_ret;
 133
 134  out:
 135         /* If the kernel crashes, we shouldn't return at all. */
 136         print_result(TEST_NAME, ret);
 137         return ret;
 138 }