From ced6f16ee919d12725840d43d007f1cfd67118df Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 24 Sep 2012 08:58:04 -0700 Subject: [PATCH] Properly handle fencepost with MALLOC_ALIGN_MASK --- ChangeLog | 6 ++++++ NEWS | 2 +- malloc/arena.c | 10 +++++++--- 3 files changed, 14 insertions(+), 4 deletions(-) diff --git a/ChangeLog b/ChangeLog index b8c492e058..e3329b4359 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2012-09-24 H.J. Lu + + [BZ #14562] + * malloc/arena.c (heap_trim): Properly get fencepost and adjust + new chunk size with MALLOC_ALIGN_MASK. + 2012-09-24 Joseph Myers [BZ #5044] diff --git a/NEWS b/NEWS index 84c05d5fed..33f86a1716 100644 --- a/NEWS +++ b/NEWS @@ -14,7 +14,7 @@ Version 2.17 14151, 14154, 14157, 14166, 14173, 14195, 14237, 14252, 14283, 14298, 14303, 14307, 14328, 14331, 14336, 14337, 14347, 14349, 14459, 14476, 14505, 14510, 14516, 14518, 14519, 14532, 14538, 14544, 14545, 14576, - 14579, 14583, 14587. + 14579, 14583, 14587, 14562. * Support for STT_GNU_IFUNC symbols added for s390 and s390x. Optimized versions of memcpy, memset, and memcmp added for System z10 and diff --git a/malloc/arena.c b/malloc/arena.c index 97c0b909cc..f24e76c4f6 100644 --- a/malloc/arena.c +++ b/malloc/arena.c @@ -655,15 +655,19 @@ 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, prev_size, 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)); + prev_size = prev_heap->size - (MINSIZE-2*SIZE_SZ); + p = chunk_at_offset(prev_heap, prev_size); + /* fencepost must be properly aligned. */ + misalign = ((long) p) & MALLOC_ALIGN_MASK; + p = chunk_at_offset(prev_heap, prev_size - misalign); 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;