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authorH.J. Lu <hjl.tools@gmail.com>2012-09-08 15:36:50 -0700
committerH.J. Lu <hjl.tools@gmail.com>2012-09-08 15:36:50 -0700
commit67d875851e833ab93dd8aa5fb934e79d094da48d (patch)
tree8623c1b2f9eb472c05cab2a8a29dd29587c0bd1b
parent3d9b46b3500566163815747173002d3d0bbb9b2f (diff)
downloadglibc-hjl/pr14562/master.zip
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Properly handle fencepost with MALLOC_ALIGN_MASKhjl/pr14562/master
-rw-r--r--ChangeLog.pr145625
-rw-r--r--malloc/arena.c7
2 files changed, 10 insertions, 2 deletions
diff --git a/ChangeLog.pr14562 b/ChangeLog.pr14562
new file mode 100644
index 0000000..b92843d
--- /dev/null
+++ b/ChangeLog.pr14562
@@ -0,0 +1,5 @@
+2012-09-08 H.J. Lu <hongjiu.lu@intel.com>
+
+ [BZ #14562]
+ * malloc/arena.c (heap_trim): Properly get fencepost and adjust
+ new chunk size with MALLOC_ALIGN_MASK.
diff --git a/malloc/arena.c b/malloc/arena.c
index 97c0b90..dd4f3e3 100644
--- a/malloc/arena.c
+++ b/malloc/arena.c
@@ -655,15 +655,18 @@ heap_trim(heap_info *heap, size_t pad)
unsigned long pagesz = GLRO(dl_pagesize);
mchunkptr top_chunk = top(ar_ptr), p, bck, fwd;
heap_info *prev_heap;
- long new_size, top_size, extra;
+ long new_size, top_size, extra, misalign;
/* Can this heap go away completely? */
while(top_chunk == chunk_at_offset(heap, sizeof(*heap))) {
prev_heap = heap->prev;
p = chunk_at_offset(prev_heap, prev_heap->size - (MINSIZE-2*SIZE_SZ));
+ /* fencepost must be properly aligned. */
+ misalign = ((long) p) & MALLOC_ALIGN_MASK;
+ p = (mchunkptr)(((unsigned long) p) & ~MALLOC_ALIGN_MASK);
assert(p->size == (0|PREV_INUSE)); /* must be fencepost */
p = prev_chunk(p);
- new_size = chunksize(p) + (MINSIZE-2*SIZE_SZ);
+ new_size = chunksize(p) + (MINSIZE-2*SIZE_SZ) + misalign;
assert(new_size>0 && new_size<(long)(2*MINSIZE));
if(!prev_inuse(p))
new_size += p->prev_size;