gistfile1.diff

diff --git a/mono/metadata/sgen-gc.c b/mono/metadata/sgen-gc.c
index d4f309b..ab9b1f9 100644
--- a/mono/metadata/sgen-gc.c
+++ b/mono/metadata/sgen-gc.c
@@ -6913,12 +6913,17 @@ mono_gc_make_root_descr_all_refs (int numbits)
 {
 	gsize *gc_bitmap;
 	void *descr;
+	int num_bytes = numbits / 8;
 
 	if (numbits < 32 && all_ref_root_descrs [numbits])
 		return all_ref_root_descrs [numbits];
 
 	gc_bitmap = g_malloc0 (ALIGN_TO (numbits, 8) + 1);
-	memset (gc_bitmap, 0xff, numbits / 8);
+	memset (gc_bitmap, 0xff, num_bytes);
+	if (numbits < ((sizeof (*gc_bitmap) * 8) - ROOT_DESC_TYPE_SHIFT))
+		gc_bitmap [0] = GUINT64_TO_LE (gc_bitmap [0]);
+	else if (numbits && num_bytes % (sizeof (*gc_bitmap)))
+		gc_bitmap [num_bytes / 8] = GUINT64_TO_LE (gc_bitmap [num_bytes / 8]);
 	if (numbits % 8)
 		gc_bitmap [numbits / 8] = (1 << (numbits % 8)) - 1;
 	descr = mono_gc_make_descr_from_bitmap (gc_bitmap, numbits);