// other threads, so mp is usually not getg().m.
	// In fact mp may not even be stopped.
	// See golang.org/issue/17165.
	getg().m.mallocing++

	var u unwinder
	var stk [maxCPUProfStack]uintptr
	n := 0
	if mp.ncgo > 0 && mp.curg != nil && mp.curg.syscallpc != 0 && mp.curg.syscallsp != 0 {
		cgoOff := 0
		// Check cgoCallersUse to make sure that we are not

	PT_SUNW_EH_FRAME ProgType = 0x6474e550 /* Frame unwind information */
	PT_SUNWSTACK     ProgType = 0x6ffffffb /* Stack segment */

	PT_HIOS ProgType = 0x6fffffff /* Last OS-specific. */

	PT_LOPROC ProgType = 0x70000000 /* First processor-specific type. */

	PT_ARM_ARCHEXT ProgType = 0x70000000 /* Architecture compatibility */
	PT_ARM_EXIDX   ProgType = 0x70000001 /* Exception unwind tables */

	if !x {
		t.Fatal("nestedCall did not call func")
	}
}

func testCallbackGC(t *testing.T) {
	nestedCall(runtime.GC)
}

func testCallbackPanic(t *testing.T) {
	// Make sure panic during callback unwinds properly.
	if lockedOSThread() {
		t.Fatal("locked OS thread on entry to TestCallbackPanic")
	}
	defer func() {
		s := recover()
		if s == nil {
			t.Fatal("did not panic")
		}