/*
* Copyright (C) 2011-2017 Red Hat, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*/
/* thp02 - detect mremap bug when THP is enabled.
*
* There was a bug in mremap THP support, sometimes crash happened
* due to the following reason according to developers:
*
* "alloc_new_pmd was forcing the allocation of a pte before calling
* move_huge_page and that resulted in a VM_BUG_ON in move_huge_page
* because the pmd wasn't zero."
*
* There are 4 cases to test this bug:
*
* 1) old_addr hpage aligned, old_end not hpage aligned, new_addr
* hpage aligned;
* 2) old_addr hpage aligned, old_end not hpage aligned, new_addr not
* hpage aligned;
* 3) old_addr not hpage aligned, old_end hpage aligned, new_addr
* hpage aligned;
* 4) old_addr not hpage aligned, old_end hpage aligned, new_addr not
* hpage aligned.
*
*/
#define _GNU_SOURCE
#include "config.h"
#include <sys/types.h>
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "mem.h"
#ifdef HAVE_MREMAP_FIXED
static int ps;
static long hps, size;
static void *p, *p2, *p3, *p4;
static void do_mremap(void)
{
int i;
void *old_addr, *new_addr;
for (i = 0; i < 4; i++) {
p = SAFE_MEMALIGN(hps, size);
p2 = SAFE_MEMALIGN(hps, size);
p3 = SAFE_MEMALIGN(hps, size);
memset(p, 0xff, size);
memset(p2, 0xff, size);
memset(p3, 0x77, size);
/*
* Will try to do the following 4 mremaps cases:
* mremap(p, size-ps, size-ps, flag, p3);
* mremap(p, size-ps, size-ps, flag, p3+ps);
* mremap(p+ps, size-ps, size-ps, flag, p3);
* mremap(p+ps, size-ps, size-ps, flag, p3+ps);
*/
old_addr = p + ps * (i >> 1);
new_addr = p3 + ps * (i & 1);
tst_res(TINFO, "mremap %p to %p", old_addr, new_addr);
p4 = mremap(old_addr, size - ps, size - ps,
MREMAP_FIXED | MREMAP_MAYMOVE, new_addr);
if (p4 == MAP_FAILED)
tst_brk(TBROK | TERRNO, "mremap");
if (memcmp(p4, p2, size - ps))
tst_brk(TBROK, "mremap bug");
}
tst_res(TPASS, "Still alive.");
}
static void setup(void)
{
if (access(PATH_THP, F_OK) == -1)
tst_brk(TCONF, "THP not enabled in kernel?");
check_hugepage();
ps = sysconf(_SC_PAGESIZE);
hps = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
size = hps * 4;
}
static struct tst_test test = {
.needs_root = 1,
.setup = setup,
.test_all = do_mremap,
};
#else
TST_TEST_TCONF("MREMAP_FIXED not present in <sys/mman.h>");
#endif /* HAVE_MREMAP_FIXED */