57 lines
1.9 KiB
C
57 lines
1.9 KiB
C
/* Test that malloc tcache catches double free.
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Copyright (C) 2018-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <malloc.h>
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#include <string.h>
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/* Prevent GCC from optimizing away any malloc/free pairs. */
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#pragma GCC optimize ("O0")
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static int
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do_test (void)
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{
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/* Do two allocation of any size that fit in tcache, and one that
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doesn't. */
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int ** volatile a = malloc (32);
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int ** volatile b = malloc (32);
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/* This is just under the mmap threshold. */
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int ** volatile c = malloc (127 * 1024);
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/* The invalid "tcache bucket" we might dereference will likely end
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up somewhere within this memory block, so make all the accidental
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"next" pointers cause segfaults. BZ #23907. */
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memset (c, 0xff, 127 * 1024);
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free (a); // puts in tcache
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/* A is now free and contains the key we use to detect in-tcache.
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Copy the key to the other chunks. */
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memcpy (b, a, 32);
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memcpy (c, a, 32);
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/* This free tests the "are we in the tcache already" loop with a
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VALID bin but "coincidental" matching key. */
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free (b); // should NOT abort
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/* This free tests the "is it a valid tcache bin" test. */
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free (c); // should NOT abort
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return 0;
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}
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#include <support/test-driver.c>
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