malloc_usable_size: Use correct size for dumped fake mapped chunks

The adjustment for the size computation in commit
1e8a8875d69e36d2890b223ffe8853a8ff0c9512 is needed in
malloc_usable_size, too.

2 files changed, 11 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 4028db2fd9..2989d21940 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2016-06-11  Florian Weimer  <fweimer@redhat.com>
 
+	* malloc/malloc.c (musable): Return correct size for dumped fake
+	mmapped chunk.
+
+2016-06-11  Florian Weimer  <fweimer@redhat.com>
+
 	[BZ #20222]
 	* libio/iofopncook.c (_IO_cookie_read): Demangle callback pointer.
 	(_IO_cookie_write): Likewise.
diff --git a/malloc/malloc.c b/malloc/malloc.c
index ac0f751593..21a912a6d1 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -4622,7 +4622,12 @@ musable (void *mem)
         return malloc_check_get_size (p);
 
       if (chunk_is_mmapped (p))
-        return chunksize (p) - 2 * SIZE_SZ;
+	{
+	  if (DUMPED_MAIN_ARENA_CHUNK (p))
+	    return chunksize (p) - SIZE_SZ;
+	  else
+	    return chunksize (p) - 2 * SIZE_SZ;
+	}
       else if (inuse (p))
         return chunksize (p) - SIZE_SZ;
     }