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 <dvhart@linux.intel.com> 13 * 14 * HISTORY 15 * 2009-Nov-9: Initial version by Darren Hart <dvhart@linux.intel.com> 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 } 136