#define disable_expand(M) ((M)->mflags |= USE_NOEXPAND_BIT)
#define use_trace(M) ((M)->mflags & USE_TRACE_BIT)
#define enable_trace(M) ((M)->mflags |= USE_TRACE_BIT)
-#define disable_trace(M) ((M)->mflags |= USE_TRACE_BIT)
+#define disable_trace(M) ((M)->mflags &= ~USE_TRACE_BIT)
#define set_lock(M,L)\
((M)->mflags = (L)?\