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98 lines
2.6 KiB
98 lines
2.6 KiB
/*
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* Copyright (C) 2012-2017 Red Hat, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
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* the GNU General Public License for more details.
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*/
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/* thp03 - Case for spliting unaligned memory.
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* - System will panic if failed.
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*
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* Modified form a reproducer for
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* https://patchwork.kernel.org/patch/1358441/
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* Kernel Commit id: 027ef6c87853b0a9df53175063028edb4950d476
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* There was a bug in THP, will crash happened due to the following
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* reason according to developers:
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*
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* most VM places are using pmd_none but a few are still using
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* pmd_present. The meaning is about the same for the pmd. However
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* pmd_present would return the wrong value on PROT_NONE ranges or in
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* case of a non reproducible race with split_huge_page.
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* When the code using pmd_present gets a false negative, the kernel will
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* crash. It's just an annoying DoS with a BUG_ON triggering: no memory
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* corruption and no data corruption (nor userland nor kernel).
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*/
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#include <sys/mman.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <fcntl.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include "mem.h"
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#include "lapi/mmap.h"
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static void thp_test(void);
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static long hugepage_size;
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static long unaligned_size;
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static long page_size;
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static void thp_test(void)
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{
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void *p;
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p = SAFE_MMAP(NULL, unaligned_size, PROT_READ | PROT_WRITE,
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MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
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memset(p, 0x00, unaligned_size);
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if (mprotect(p, unaligned_size, PROT_NONE) == -1)
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tst_brk(TBROK | TERRNO, "mprotect");
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if (madvise(p + hugepage_size, page_size, MADV_MERGEABLE) == -1) {
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if (errno == EINVAL) {
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tst_brk(TCONF,
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"MADV_MERGEABLE is not enabled/supported");
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} else {
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tst_brk(TBROK | TERRNO, "madvise");
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}
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}
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switch (SAFE_FORK()) {
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case 0:
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exit(0);
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default:
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SAFE_WAITPID(-1, NULL, 0);
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}
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tst_res(TPASS, "system didn't crash, pass.");
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munmap(p, unaligned_size);
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}
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static void setup(void)
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{
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if (access(PATH_THP, F_OK) == -1)
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tst_brk(TCONF, "THP not enabled in kernel?");
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check_hugepage();
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hugepage_size = SAFE_READ_MEMINFO("Hugepagesize:") * KB;
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unaligned_size = hugepage_size * 4 - 1;
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page_size = SAFE_SYSCONF(_SC_PAGESIZE);
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}
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static struct tst_test test = {
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.needs_root = 1,
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.forks_child = 1,
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.setup = setup,
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.test_all = thp_test,
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};
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