121 lines
2.6 KiB
C
121 lines
2.6 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright (C) 2011-2017 Red Hat, Inc.
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*/
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/*\
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* [Description]
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*
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* Test for detecting mremap bug when THP is enabled.
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*
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* There was a bug in mremap THP support, sometimes causing crash
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* due to the following reason:
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*
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* "alloc_new_pmd was forcing the allocation of a pte before calling
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* move_huge_page and that resulted in a VM_BUG_ON in move_huge_page
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* because the pmd wasn't zero."
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*
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* There are 4 cases to test this bug:
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*
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* 1. old_addr hpage aligned, old_end not hpage aligned, new_addr
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* hpage aligned
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*
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* 2. old_addr hpage aligned, old_end not hpage aligned, new_addr not
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* hpage aligned
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*
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* 3. old_addr not hpage aligned, old_end hpage aligned, new_addr
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* hpage aligned
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*
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* 4. old_addr not hpage aligned, old_end hpage aligned, new_addr not
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* hpage aligned
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*/
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#define _GNU_SOURCE
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#include "config.h"
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#include <sys/types.h>
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#include <sys/mman.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "mem.h"
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static int ps;
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static long hps, size;
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/*
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* Will try to do the following 4 mremaps cases:
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* mremap(p, size-ps, size-ps, flag, p2);
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* mremap(p, size-ps, size-ps, flag, p2+ps);
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* mremap(p+ps, size-ps, size-ps, flag, p2);
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* mremap(p+ps, size-ps, size-ps, flag, p2+ps);
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*/
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static void do_child(int i)
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{
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long j, remap_size;
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unsigned char *p1, *p2, *ret, *old_addr, *new_addr;
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p1 = SAFE_MEMALIGN(hps, size);
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p2 = SAFE_MEMALIGN(hps, size);
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memset(p1, 0xff, size);
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memset(p2, 0x77, size);
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old_addr = p1 + ps * (i >> 1);
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new_addr = p2 + ps * (i & 1);
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remap_size = size - ps;
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tst_res(TINFO, "mremap (%p-%p) to (%p-%p)",
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old_addr, old_addr + remap_size,
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new_addr, new_addr + remap_size);
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ret = mremap(old_addr, remap_size, remap_size,
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MREMAP_FIXED | MREMAP_MAYMOVE, new_addr);
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if (ret == MAP_FAILED)
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tst_brk(TBROK | TERRNO, "mremap");
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for (j = 0; j < remap_size; j++) {
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if (ret[j] != 0xff)
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tst_brk(TBROK, "mremap bug");
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}
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exit(0);
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}
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static void do_mremap(void)
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{
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int i;
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for (i = 0; i < 4; i++) {
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if (SAFE_FORK() == 0)
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do_child(i);
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tst_reap_children();
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}
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tst_res(TPASS, "Still alive.");
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}
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static void setup(void)
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{
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long memfree;
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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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ps = sysconf(_SC_PAGESIZE);
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hps = SAFE_READ_MEMINFO("Hugepagesize:") * 1024;
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size = hps * 4;
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memfree = (SAFE_READ_MEMINFO("MemFree:") * 1024 +
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SAFE_READ_MEMINFO("Cached:") * 1024);
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if (memfree < size * 2)
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tst_brk(TCONF, "not enough memory");
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}
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static struct tst_test test = {
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.setup = setup,
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.test_all = do_mremap,
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.forks_child = 1,
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};
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