want := "OK\n"
	if got != want {
		t.Fatalf("expected %q, but got %q", want, got)
	}
}

func TestScavengedBitsCleared(t *testing.T) {
	var mismatches [128]BitsMismatch
	if n, ok := CheckScavengedBitsCleared(mismatches[:]); !ok {
		t.Errorf("uncleared scavenged bits")
		for _, m := range mismatches[:n] {
			t.Logf("\t@ address 0x%x", m.Base)
			t.Logf("\t|  got: %064b", m.Got)
			t.Logf("\t| want: %064b", m.Want)

func PageBase(c ChunkIdx, pageIdx uint) uintptr {
	return chunkBase(chunkIdx(c)) + uintptr(pageIdx)*pageSize
}

type BitsMismatch struct {
	Base      uintptr
	Got, Want uint64
}

func CheckScavengedBitsCleared(mismatches []BitsMismatch) (n int, ok bool) {
	ok = true

	// Run on the system stack to avoid stack growth allocation.
	systemstack(func() {
		getg().m.mallocing++