diff --git a/src/pkg/runtime/proc.c b/src/pkg/runtime/proc.c
index 74e92a63fa..3ce281fc77 100644
--- a/src/pkg/runtime/proc.c
+++ b/src/pkg/runtime/proc.c
@@ -2175,6 +2175,12 @@ preemptone(P *p)
 	M *mp;
 	G *gp;
 
+// Preemption requires more robust traceback routines.
+// For now, disable.
+// The if(1) silences a compiler warning about the rest of the
+// function being unreachable.
+if(1) return;
+
 	mp = p->m;
 	if(mp == nil || mp == m)
 		return;