cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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futex_requeue_pi_mismatched_ops.c (3205B)

      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
     31futex_t f1 = FUTEX_INITIALIZER;
     32futex_t f2 = FUTEX_INITIALIZER;
     33int child_ret = 0;
     34
     35void 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
     44void *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
     54int 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}