runtime: usleep in TestWeakToStrongMarkTermination

There's a subtle bug in this test (big surprise): time.Sleep allocates, so the time.Sleep(100*time.Millisecond) before unblocking gcMarkDone might itself end up in gcMarkDone. Work around this by using usleep here instead. Fixes #70532. Change-Id: I4c642ebb12f737cdb0d79ccff64b6059fc3d8b34 Reviewed-on: https://go-review.googlesource.com/c/go/+/636155 Reviewed-by: Cherry Mui <[email protected]> LUCI-TryBot-Result: Go LUCI <[email protected]>
golang · Dec 16, 2024 · 3bd08b9 · 3bd08b9
1 parent 18b5435
commit 3bd08b9
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/src/runtime/gc_test.go b/src/runtime/gc_test.go
@@ -834,7 +834,11 @@ func TestWeakToStrongMarkTermination(t *testing.T) {
 		done <- struct{}{}
 	}()
 	go func() {
-		time.Sleep(100 * time.Millisecond)
+		// Usleep here instead of time.Sleep. time.Sleep
+		// can allocate, and if we get unlucky, then it
+		// can end up stuck in gcMarkDone with nothing to
+		// wake it.
+		runtime.Usleep(100000) // 100ms
 
 		// Let mark termination continue.
 		runtime.SetSpinInGCMarkDone(false)