diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index ba3e21ae2e..dd6d79f8ec 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -536,7 +536,7 @@ func sighandler(sig uint32, info *siginfo, ctxt unsafe.Pointer, gp *g) {
 		return
 	}
 
-	if sig == sigPreempt {
+	if sig == sigPreempt && debug.asyncpreemptoff == 0 {
 		// Might be a preemption signal.
 		doSigPreempt(gp, c)
 		// Even if this was definitely a preemption signal, it