/*
* libhugetlbfs - Easy use of Linux hugepages
* Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
* Copyright (C) 2006 Hugh Dickins <hugh@veritas.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#define _LARGEFILE64_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <sys/mman.h>
#include <hugetlbfs.h>
#include "hugetests.h"
/*
* Test rationale:
*
* At one stage, a misconversion of hugetlb_vmtruncate_list to a
* prio_tree meant that on 32-bit machines, truncates at or above 4GB
* could truncate lower pages, resulting in BUG_ON()s.
*
* WARNING: The offsets and addresses used within are specifically
* calculated to trigger the bug as it existed. Don't mess with them
* unless you *really* know what you're doing.
*
* The kernel bug in question was fixed with commit
* 856fc29505556cf263f3dcda2533cf3766c14ab6.
*/
#define FOURGIG ((off64_t)0x100000000ULL)
static void sigbus_handler_fail(int signum, siginfo_t *si, void *uc)
{
FAIL("Unexpected SIGBUS");
}
static void sigbus_handler_pass(int signum, siginfo_t *si, void *uc)
{
PASS();
}
int main(int argc, char *argv[])
{
int page_size;
long hpage_size;
long long buggy_offset, truncate_point;
int fd;
void *p, *q;
volatile unsigned int *pi, *qi;
int err;
struct sigaction sa_fail = {
.sa_sigaction = sigbus_handler_fail,
.sa_flags = SA_SIGINFO,
};
struct sigaction sa_pass = {
.sa_sigaction = sigbus_handler_pass,
.sa_flags = SA_SIGINFO,
};
test_init(argc, argv);
page_size = getpagesize();
hpage_size = check_hugepagesize();
truncate_point = FOURGIG;
if (hpage_size > truncate_point)
CONFIG("Huge page size is too large");
if (truncate_point % hpage_size > 0)
CONFIG("Truncation point is not aligned to huge page size");
check_free_huge_pages(3);
fd = hugetlbfs_unlinked_fd();
if (fd < 0)
FAIL("hugetlbfs_unlinked_fd()");
buggy_offset = truncate_point / (hpage_size / page_size);
buggy_offset = ALIGN(buggy_offset, hpage_size);
verbose_printf("Mapping 3 hpages at offset 0x%llx...", truncate_point);
/* First get arena of three hpages size, at file offset 4GB */
q = mmap64(NULL, 3*hpage_size, PROT_READ|PROT_WRITE,
MAP_PRIVATE, fd, truncate_point);
if (q == MAP_FAILED)
FAIL("mmap() offset 4GB: %s", strerror(errno));
verbose_printf("mapped at %p\n", q);
qi = q;
/* Touch the high page */
*qi = 0;
/* This part of the test makes the problem more obvious, but
* is not essential. It can't be done on segmented powerpc, where
* segment restrictions prohibit us from performing such a
* mapping, so skip it there. Similarly, ia64's address space
* restrictions prevent this. */
#if (defined(__powerpc__) && defined(PPC_NO_SEGMENTS)) \
|| !defined(__powerpc__) && !defined(__powerpc64__) \
&& !defined(__ia64__)
/* Replace middle hpage by tinypage mapping to trigger
* nr_ptes BUG */
verbose_printf("Replacing map at %p-%p...", q + hpage_size,
q + hpage_size + hpage_size-1);
p = mmap64(q + hpage_size, hpage_size, PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_PRIVATE|MAP_ANON, -1, 0);
if (p != q + hpage_size)
FAIL("mmap() before low hpage");
verbose_printf("done\n");
pi = p;
/* Touch one page to allocate its page table */
*pi = 0;
#endif
/* Replace top hpage by hpage mapping at confusing file offset */
verbose_printf("Replacing map at %p with map from offset 0x%llx...",
q + 2*hpage_size, buggy_offset);
p = mmap64(q + 2*hpage_size, hpage_size, PROT_READ|PROT_WRITE,
MAP_FIXED|MAP_PRIVATE, fd, buggy_offset);
if (p != q + 2*hpage_size)
FAIL("mmap() buggy offset 0x%llx", buggy_offset);
verbose_printf("done\n");
pi = p;
/* Touch the low page with something non-zero */
*pi = 1;
verbose_printf("Truncating at 0x%llx...", truncate_point);
err = ftruncate64(fd, truncate_point);
if (err)
FAIL("ftruncate(): %s", strerror(errno));
verbose_printf("done\n");
err = sigaction(SIGBUS, &sa_fail, NULL);
if (err)
FAIL("sigaction() fail: %s", strerror(errno));
if (*pi != 1)
FAIL("Data 1 has changed to %u", *pi);
err = sigaction(SIGBUS, &sa_pass, NULL);
if (err)
FAIL("sigaction() pass: %s", strerror(errno));
*qi;
/* Should have SIGBUSed above */
FAIL("Didn't SIGBUS on truncated page.");
}