133 lines
3.0 KiB
C
133 lines
3.0 KiB
C
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// SPDX-License-Identifier: LGPL-2.1-or-later
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/*
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* Copyright (C) 2005-2006 David Gibson & Adam Litke, IBM Corporation.
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* Author: David Gibson & Adam Litke
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*/
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/*\
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* [Description]
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*
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* Certain kernels have a bug where brk() does not perform the same
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* checks that a MAP_FIXED mmap() will, allowing brk() to create a
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* normal page VMA in a hugepage only address region. This can lead
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* to oopses or other badness.
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*/
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#define _GNU_SOURCE
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#include <stdio.h>
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#include <sys/mount.h>
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#include <limits.h>
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#include <sys/param.h>
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#include <sys/types.h>
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#include "hugetlb.h"
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#include "tst_safe_stdio.h"
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#define MNTPOINT "hugetlbfs/"
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static long hpage_size;
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static int huge_fd = -1;
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#ifdef __powerpc64__
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static int arch_has_slice_support(void)
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{
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char mmu_type[16];
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SAFE_FILE_LINES_SCANF("/proc/cpuinfo", "MMU : %16s", mmu_type);
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return strcmp(mmu_type, "Hash") == 0;
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}
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static void *next_chunk(void *addr)
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{
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if (!arch_has_slice_support())
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return PALIGN(addr, hpage_size);
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if ((unsigned long)addr < 0x100000000UL)
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/* 256M segments below 4G */
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return PALIGN(addr, 0x10000000UL);
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/* 1TB segments above */
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return PALIGN(addr, 0x10000000000UL);
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}
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#elif defined(__powerpc__)
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static void *next_chunk(void *addr)
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{
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if (tst_kernel_bits() == 32)
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return PALIGN(addr, hpage_size);
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else
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return PALIGN(addr, 0x10000000UL);
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}
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#elif defined(__ia64__)
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static void *next_chunk(void *addr)
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{
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return PALIGN(addr, 0x8000000000000000UL);
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}
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#else
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static void *next_chunk(void *addr)
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{
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return PALIGN(addr, hpage_size);
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}
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#endif
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static void run_test(void)
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{
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void *brk0, *hugemap_addr, *newbrk;
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char *p;
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int err;
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brk0 = sbrk(0);
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tst_res(TINFO, "Initial break at %p", brk0);
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hugemap_addr = next_chunk(brk0) + hpage_size;
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p = SAFE_MMAP(hugemap_addr, hpage_size, PROT_READ|PROT_WRITE,
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MAP_PRIVATE|MAP_FIXED, huge_fd, 0);
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if (p != hugemap_addr) {
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tst_res(TFAIL, "mmap() at unexpected address %p instead of %p\n", p,
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hugemap_addr);
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goto cleanup;
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}
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newbrk = next_chunk(brk0) + getpagesize();
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err = brk((void *)newbrk);
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if (err == -1) {
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/* Failing the brk() is an acceptable kernel response */
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tst_res(TPASS, "Failing the brk at %p is an acceptable response",
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newbrk);
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} else {
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/* Suceeding the brk() is acceptable if the new memory is
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* properly accesible and we don't have a kernel blow up when
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* we touch it.
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*/
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tst_res(TINFO, "New break at %p", newbrk);
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memset(brk0, 0, newbrk-brk0);
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tst_res(TPASS, "memory is accessible, hence successful brk() is "
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"an acceptable response");
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}
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cleanup:
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SAFE_MUNMAP(p, hpage_size);
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err = brk(brk0);
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if (err == -1)
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tst_brk(TBROK, "Failed to set break at the original position");
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}
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static void setup(void)
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{
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hpage_size = SAFE_READ_MEMINFO(MEMINFO_HPAGE_SIZE)*1024;
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huge_fd = tst_creat_unlinked(MNTPOINT, 0);
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}
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static void cleanup(void)
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{
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SAFE_CLOSE(huge_fd);
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}
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static struct tst_test test = {
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.needs_root = 1,
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.mntpoint = MNTPOINT,
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.needs_hugetlbfs = 1,
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.taint_check = TST_TAINT_D | TST_TAINT_W,
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.setup = setup,
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.cleanup = cleanup,
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.test_all = run_test,
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.hugepages = {1, TST_NEEDS},
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};
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