}

		// Check that the actual results equal the expected results.
		if !c.r0.Eq(r) {
			t.Errorf("%s: clip rectangle want %v got %v", c.desc, c.r0, r)
			continue
		}
		if !c.sp0.Eq(sp) {
			t.Errorf("%s: sp want %v got %v", c.desc, c.sp0, sp)
			continue
		}
		if !c.nilMask {
			if !c.mp0.Eq(mp) {
				t.Errorf("%s: mp want %v got %v", c.desc, c.mp0, mp)
				continue
			}
		}

		throw("cannot trace user goroutine on its own stack")
	}

	if pc0 == ^uintptr(0) && sp0 == ^uintptr(0) { // Signal to fetch saved values from gp.
		if gp.syscallsp != 0 {
			pc0 = gp.syscallpc
			sp0 = gp.syscallsp
			if usesLR {
				lr0 = 0
			}
		} else {
			pc0 = gp.sched.pc
			sp0 = gp.sched.sp
			if usesLR {
				lr0 = gp.sched.lr
			}
		}
	}

	var frame stkframe