malloc: Correct size computation in realloc for dumped fake mmapped chunks

For regular mmapped chunks there are two size fields (hence a reduction
by 2 * SIZE_SZ bytes), but for fake chunks, we only have one size field,
so we need to subtract SIZE_SZ bytes.

This was initially reported as Emacs bug 23726.

1 files changed, 7 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 20b3dc0194..6ceb2dfeec 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-06-08  Florian Weimer  <fweimer@redhat.com>
+
+	Emacs bug 23726.
+	* malloc/malloc.c (dumped_main_arena_start): Update comment.
+	(__libc_realloc): Correct size computation for dumped fake mmapped
+	chunks.
+
 2016-06-07  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #20219]