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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /******************************************************************************
   3  *
   4  *   Copyright © International Business Machines  Corp., 2009
   5  *
   6  * DESCRIPTION
   7  *      1. Block a thread using FUTEX_WAIT
   8  *      2. Attempt to use FUTEX_CMP_REQUEUE_PI on the futex from 1.
   9  *      3. The kernel must detect the mismatch and return -EINVAL.
  10  *
  11  * AUTHOR
  12  *      Darren Hart <[email protected]>
  13  *
  14  * HISTORY
  15  *      2009-Nov-9: Initial version by Darren Hart <[email protected]>
  16  *
  17  *****************************************************************************/
  18
  19 #include <errno.h>
  20 #include <getopt.h>
  21 #include <pthread.h>
  22 #include <stdio.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <time.h>
  26 #include "futextest.h"
  27 #include "logging.h"
  28
  29 #define TEST_NAME "futex-requeue-pi-mismatched-ops"
  30
  31 futex_t f1 = FUTEX_INITIALIZER;
  32 futex_t f2 = FUTEX_INITIALIZER;
  33 int child_ret = 0;
  34
  35 void usage(char *prog)
  36 {
  37         printf("Usage: %s\n", prog);
  38         printf("  -c    Use color\n");
  39         printf("  -h    Display this help message\n");
  40         printf("  -v L  Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n",
  41                VQUIET, VCRITICAL, VINFO);
  42 }
  43
  44 void *blocking_child(void *arg)
  45 {
  46         child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
  47         if (child_ret < 0) {
  48                 child_ret = -errno;
  49                 error("futex_wait\n", errno);
  50         }
  51         return (void *)&child_ret;
  52 }
  53
  54 int main(int argc, char *argv[])
  55 {
  56         int ret = RET_PASS;
  57         pthread_t child;
  58         int c;
  59
  60         while ((c = getopt(argc, argv, "chv:")) != -1) {
  61                 switch (c) {
  62                 case 'c':
  63                         log_color(1);
  64                         break;
  65                 case 'h':
  66                         usage(basename(argv[0]));
  67                         exit(0);
  68                 case 'v':
  69                         log_verbosity(atoi(optarg));
  70                         break;
  71                 default:
  72                         usage(basename(argv[0]));
  73                         exit(1);
  74                 }
  75         }
  76
  77         ksft_print_header();
  78         ksft_set_plan(1);
  79         ksft_print_msg("%s: Detect mismatched requeue_pi operations\n",
  80                basename(argv[0]));
  81
  82         if (pthread_create(&child, NULL, blocking_child, NULL)) {
  83                 error("pthread_create\n", errno);
  84                 ret = RET_ERROR;
  85                 goto out;
  86         }
  87         /* Allow the child to block in the kernel. */
  88         sleep(1);
  89
  90         /*
  91          * The kernel should detect the waiter did not setup the
  92          * q->requeue_pi_key and return -EINVAL. If it does not,
  93          * it likely gave the lock to the child, which is now hung
  94          * in the kernel.
  95          */
  96         ret = futex_cmp_requeue_pi(&f1, f1, &f2, 1, 0, FUTEX_PRIVATE_FLAG);
  97         if (ret < 0) {
  98                 if (errno == EINVAL) {
  99                         /*
 100                          * The kernel correctly detected the mismatched
 101                          * requeue_pi target and aborted. Wake the child with
 102                          * FUTEX_WAKE.
 103                          */
 104                         ret = futex_wake(&f1, 1, FUTEX_PRIVATE_FLAG);
 105                         if (ret == 1) {
 106                                 ret = RET_PASS;
 107                         } else if (ret < 0) {
 108                                 error("futex_wake\n", errno);
 109                                 ret = RET_ERROR;
 110                         } else {
 111                                 error("futex_wake did not wake the child\n", 0);
 112                                 ret = RET_ERROR;
 113                         }
 114                 } else {
 115                         error("futex_cmp_requeue_pi\n", errno);
 116                         ret = RET_ERROR;
 117                 }
 118         } else if (ret > 0) {
 119                 fail("futex_cmp_requeue_pi failed to detect the mismatch\n");
 120                 ret = RET_FAIL;
 121         } else {
 122                 error("futex_cmp_requeue_pi found no waiters\n", 0);
 123                 ret = RET_ERROR;
 124         }
 125
 126         pthread_join(child, NULL);
 127
 128         if (!ret)
 129                 ret = child_ret;
 130
 131  out:
 132         /* If the kernel crashes, we shouldn't return at all. */
 133         print_result(TEST_NAME, ret);
 134         return ret;
 135 }