diff --git a/libfdt/fdt_rw.c b/libfdt/fdt_rw.c
index cd06178..5c27a67 100644
--- a/libfdt/fdt_rw.c
+++ b/libfdt/fdt_rw.c
@@ -410,6 +410,8 @@
 		struct_size = 0;
 		while (fdt_next_tag(fdt, struct_size, &struct_size) != FDT_END)
 			;
+		if (struct_size < 0)
+			return struct_size;
 	}
 
 	if (!_fdt_blocks_misordered(fdt, mem_rsv_size, struct_size)) {