--- a/usr/src/uts/sun4/os/trap.c	Fri Mar 09 15:42:52 2007 -0800
+++ b/usr/src/uts/sun4/os/trap.c	Fri Mar 09 15:55:28 2007 -0800
@@ -1564,7 +1564,7 @@
 		CL_TRAPRET(curthread);
 		thread_unlock(curthread);
 	}
-	if (CPU->cpu_runrun)
+	if (CPU->cpu_runrun || curthread->t_schedflag & TS_ANYWAITQ)
 		preempt();
 	if (lwp->lwp_pcb.pcb_step != STEP_NONE)
 		prdostep();