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Make free chunk size a multiple of MALLOC_ALIGNMENT

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H.J. Lu
2012-05-24 17:50:28 -07:00
parent 6bcc8b3ff9
commit 347c92e9e7
2 changed files with 13 additions and 4 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2012-05-24 H.J. Lu <hongjiu.lu@intel.com>
[BZ #13576]
* malloc/malloc.c (sYSMALLOc): Free the old top chunk with a
multiple of MALLOC_ALIGNMENT in size.
(_int_free): Check chunk size is a multiple of MALLOC_ALIGNMENT.
2012-05-24 Joseph Myers <joseph@codesourcery.com> 2012-05-24 Joseph Myers <joseph@codesourcery.com>
* conform/data/stdio.h-data (BUFSIZ): Use macro-int-constant. * conform/data/stdio.h-data (BUFSIZ): Use macro-int-constant.

10
malloc/malloc.c
View File

@ -2396,11 +2396,12 @@ static void* sysmalloc(INTERNAL_SIZE_T nb, mstate av)
top(av) = chunk_at_offset(heap, sizeof(*heap)); top(av) = chunk_at_offset(heap, sizeof(*heap));
set_head(top(av), (heap->size - sizeof(*heap)) | PREV_INUSE); set_head(top(av), (heap->size - sizeof(*heap)) | PREV_INUSE);
/* Setup fencepost and free the old top chunk. */ /* Setup fencepost and free the old top chunk with a multiple of
MALLOC_ALIGNMENT in size. */
/* The fencepost takes at least MINSIZE bytes, because it might /* The fencepost takes at least MINSIZE bytes, because it might
become the top chunk again later. Note that a footer is set become the top chunk again later. Note that a footer is set
up, too, although the chunk is marked in use. */ up, too, although the chunk is marked in use. */
old_size -= MINSIZE; old_size = (old_size - MINSIZE) & ~MALLOC_ALIGN_MASK;
set_head(chunk_at_offset(old_top, old_size + 2*SIZE_SZ), 0|PREV_INUSE); set_head(chunk_at_offset(old_top, old_size + 2*SIZE_SZ), 0|PREV_INUSE);
if (old_size >= MINSIZE) { if (old_size >= MINSIZE) {
set_head(chunk_at_offset(old_top, old_size), (2*SIZE_SZ)|PREV_INUSE); set_head(chunk_at_offset(old_top, old_size), (2*SIZE_SZ)|PREV_INUSE);
@ -3809,8 +3810,9 @@ _int_free(mstate av, mchunkptr p, int have_lock)
malloc_printerr (check_action, errstr, chunk2mem(p)); malloc_printerr (check_action, errstr, chunk2mem(p));
return; return;
} }
/* We know that each chunk is at least MINSIZE bytes in size. */ /* We know that each chunk is at least MINSIZE bytes in size or a
if (__builtin_expect (size < MINSIZE, 0)) multiple of MALLOC_ALIGNMENT. */
if (__builtin_expect (size < MINSIZE || !aligned_OK (size), 0))
{ {
errstr = "free(): invalid size"; errstr = "free(): invalid size";
goto errout; goto errout;