diff --git a/minix/lib/libsys/asynsend.c b/minix/lib/libsys/asynsend.c
index 3f414712f..d6c19eecd 100644
--- a/minix/lib/libsys/asynsend.c
+++ b/minix/lib/libsys/asynsend.c
@@ -126,6 +126,7 @@ int fl;
   fl |= AMF_VALID;	/* Mark in use */
   msgtable[next_slot].dst = dst;
   msgtable[next_slot].msg = *mp;
+  __insn_barrier();
   msgtable[next_slot].flags = fl;		/* Has to be last. The kernel 
 					 	 * scans this table while we
 						 * are sleeping.