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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2015 Yi Zhang <wetpzy@gmail.com>
* Li Wang <liwang@redhat.com>
*
* DESCRIPTION:
*
* It is a regression test for commit:
* http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/
* commit/?id=13d60f4
*
* The implementation of futex doesn't produce unique keys for futexes
* in shared huge pages, so threads waiting on different futexes may
* end up on the same wait list. This results in incorrect threads being
* woken by FUTEX_WAKE.
*
* Needs to be run as root unless there are already enough huge pages available.
* In the fail case, which happens in the CentOS-6.6 kernel (2.6.32-504.8.1),
* the tests hangs until it times out after a 30-second wait.
*
*/
#include <stdio.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <sys/time.h>
#include <string.h>
#include "futextest.h"
#include "futex_utils.h"
#include "lapi/mmap.h"
#include "tst_safe_stdio.h"
#include "tst_safe_pthread.h"
static futex_t *futex1, *futex2;
static struct tst_ts to;
static struct futex_test_variants variants[] = {
#if (__NR_futex != __LTP__NR_INVALID_SYSCALL)
{ .fntype = FUTEX_FN_FUTEX, .tstype = TST_KERN_OLD_TIMESPEC, .desc = "syscall with old kernel spec"},
#endif
#if (__NR_futex_time64 != __LTP__NR_INVALID_SYSCALL)
{ .fntype = FUTEX_FN_FUTEX64, .tstype = TST_KERN_TIMESPEC, .desc = "syscall time64 with kernel spec"},
#endif
};
static void setup(void)
{
struct futex_test_variants *tv = &variants[tst_variant];
tst_res(TINFO, "Testing variant: %s", tv->desc);
futex_supported_by_kernel(tv->fntype);
to = tst_ts_from_ns(tv->tstype, 30 * NSEC_PER_SEC);
}
static void *wait_thread1(void *arg LTP_ATTRIBUTE_UNUSED)
{
struct futex_test_variants *tv = &variants[tst_variant];
futex_wait(tv->fntype, futex1, *futex1, &to, 0);
return NULL;
}
static void *wait_thread2(void *arg LTP_ATTRIBUTE_UNUSED)
{
struct futex_test_variants *tv = &variants[tst_variant];
int res;
errno = 0;
res = futex_wait(tv->fntype, futex2, *futex2, &to, 0);
if (!res)
tst_res(TPASS, "Hi hydra, thread2 awake!");
else
tst_res(TFAIL | TERRNO, "Bug: wait_thread2 did not wake after 30 secs.");
return NULL;
}
static void wakeup_thread2(void)
{
struct futex_test_variants *tv = &variants[tst_variant];
void *addr;
int hpsz, pgsz;
pthread_t th1, th2;
hpsz = tst_get_hugepage_size();
tst_res(TINFO, "Hugepagesize %i", hpsz);
/*allocate some shared memory*/
addr = mmap(NULL, hpsz, PROT_WRITE | PROT_READ,
MAP_SHARED | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
if (addr == MAP_FAILED) {
if (errno == ENOMEM)
tst_brk(TCONF, "Cannot allocate hugepage, memory too fragmented?");
tst_brk(TBROK | TERRNO, "Cannot allocate hugepage");
}
pgsz = getpagesize();
/*apply the first subpage to futex1*/
futex1 = addr;
*futex1 = 0;
/*apply the second subpage to futex2*/
futex2 = (futex_t *)((char *)addr + pgsz);
*futex2 = 0;
/*thread1 block on futex1 first,then thread2 block on futex2*/
SAFE_PTHREAD_CREATE(&th1, NULL, wait_thread1, NULL);
SAFE_PTHREAD_CREATE(&th2, NULL, wait_thread2, NULL);
while (wait_for_threads(2))
usleep(1000);
futex_wake(tv->fntype, futex2, 1, 0);
SAFE_PTHREAD_JOIN(th2, NULL);
futex_wake(tv->fntype, futex1, 1, 0);
SAFE_PTHREAD_JOIN(th1, NULL);
SAFE_MUNMAP(addr, hpsz);
}
static struct tst_test test = {
.setup = setup,
.test_all = wakeup_thread2,
.test_variants = ARRAY_SIZE(variants),
.needs_root = 1,
.needs_tmpdir = 1,
.hugepages = {1, TST_NEEDS},
};
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