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 } 139