diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 2cd3d71800..ac191f302f 100644
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -432,6 +432,14 @@ func dieFromSignal(sig uint32) {
 	osyield()
 	osyield()
 
+	// On Darwin we may still fail to die, because raise sends the
+	// signal to the whole process rather than just the current thread,
+	// and osyield just sleeps briefly rather than letting all other
+	// threads run. See issue 20315. Sleep longer.
+	if GOOS == "darwin" {
+		usleep(100)
+	}
+
 	// If we are still somehow running, just exit with the wrong status.
 	exit(2)
 }