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 <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
27#include "futextest.h"
28#include "kselftest_harness.h"
29
30futex_t f1 = FUTEX_INITIALIZER;
31futex_t f2 = FUTEX_INITIALIZER;
32int child_ret = 0;
33
34void *blocking_child(void *arg)
35{
36	child_ret = futex_wait(&f1, f1, NULL, FUTEX_PRIVATE_FLAG);
37	if (child_ret < 0) {
38		child_ret = -errno;
39		ksft_exit_fail_msg("futex_wait\n");
40	}
41	return (void *)&child_ret;
42}
43
44TEST(requeue_pi_mismatched_ops)
45{
46	pthread_t child;
47	int ret;
48
49	if (pthread_create(&child, NULL, blocking_child, NULL))
50		ksft_exit_fail_msg("pthread_create\n");
51
52	/* Allow the child to block in the kernel. */
53	sleep(1);
54
55	/*
56	 * The kernel should detect the waiter did not setup the
57	 * q->requeue_pi_key and return -EINVAL. If it does not,
58	 * it likely gave the lock to the child, which is now hung
59	 * in the kernel.
60	 */
61	ret = futex_cmp_requeue_pi(&f1, f1, &f2, 1, 0, FUTEX_PRIVATE_FLAG);
62	if (ret < 0) {
63		if (errno == EINVAL) {
64			/*
65			 * The kernel correctly detected the mismatched
66			 * requeue_pi target and aborted. Wake the child with
67			 * FUTEX_WAKE.
68			 */
69			ret = futex_wake(&f1, 1, FUTEX_PRIVATE_FLAG);
70			if (ret == 1)
71				ret = 0;
72			else if (ret < 0)
73				ksft_exit_fail_msg("futex_wake\n");
74			else
75				ksft_exit_fail_msg("futex_wake did not wake the child\n");
76		} else {
77			ksft_exit_fail_msg("futex_cmp_requeue_pi\n");
78		}
79	} else if (ret > 0) {
80		ksft_test_result_fail("futex_cmp_requeue_pi failed to detect the mismatch\n");
81	} else {
82		ksft_exit_fail_msg("futex_cmp_requeue_pi found no waiters\n");
83	}
84
85	pthread_join(child, NULL);
86
87	if (!ret && !child_ret)
88		ksft_test_result_pass("futex_requeue_pi_mismatched_ops passed\n");
89	else
90		ksft_test_result_pass("futex_requeue_pi_mismatched_ops failed\n");
91}
92
93TEST_HARNESS_MAIN