if gp.syscallsp != 0 {
				pcBuf[1] = gp.syscallpc
				nstk += 1 + fpTracebackPCs(unsafe.Pointer(gp.syscallbp), pcBuf[2:])
			} else {
				pcBuf[1] = gp.sched.pc
				nstk += 1 + fpTracebackPCs(unsafe.Pointer(gp.sched.bp), pcBuf[2:])
			}
		}
	}
	if nstk > 0 {
		nstk-- // skip runtime.goexit
	}
	if nstk > 0 && gp.goid == 1 {
		nstk-- // skip runtime.main
	}
	id := trace.stackTab[gen%2].put(pcBuf[:nstk])

			// do here, we only want to report full records.
			continue
		}

		// Construct the stack for insertion to the stack table.
		nstk := 1
		pcBuf[0] = logicalStackSentinel
		for ; nstk < len(pcBuf) && nstk-1 < len(stk); nstk++ {
			pcBuf[nstk] = uintptr(stk[nstk-1])
		}

		// Write out a trace event.
		w := unsafeTraceWriter(gen, trace.cpuBuf[gen%2])

		// Ensure we have a place to write to.

	b := (*bucket)(persistentalloc(size, 0, &memstats.buckhash_sys))
	b.typ = typ
	b.nstk = uintptr(nstk)
	return b
}

// stk returns the slice in b holding the stack. The caller can asssume that the
// backing array is immutable.
func (b *bucket) stk() []uintptr {
	stk := (*[maxProfStackDepth]uintptr)(add(unsafe.Pointer(b), unsafe.Sizeof(*b)))
	if b.nstk > maxProfStackDepth {
		// prove that slicing works; otherwise a failure requires a P

	locs := make(map[uint64]*Location)
	for len(b) > 0 {
		var count, nstk uint64
		count, b = parse(b)
		nstk, b = parse(b)
		if b == nil || nstk > uint64(len(b)/4) {
			return nil, nil, errUnrecognized
		}
		var sloc []*Location
		addrs := make([]uint64, nstk)
		for i := 0; i < int(nstk); i++ {
			addrs[i], b = parse(b)
		}

		if count == 0 && nstk == 1 && addrs[0] == 0 {
			// End of data marker
			break
		}

	}
	dumpint(uint64(m.NumGC))
}

func dumpmemprof_callback(b *bucket, nstk uintptr, pstk *uintptr, size, allocs, frees uintptr) {
	stk := (*[100000]uintptr)(unsafe.Pointer(pstk))
	dumpint(tagMemProf)
	dumpint(uint64(uintptr(unsafe.Pointer(b))))
	dumpint(uint64(size))
	dumpint(uint64(nstk))
	for i := uintptr(0); i < nstk; i++ {
		pc := stk[i]
		f := findfunc(pc)
		if !f.valid() {
			var buf [64]byte

// for a single contiguous record with a stack of length nstk.
func (b *profBuf) canWriteRecord(nstk int) bool {
	br := b.r.load()
	bw := b.w.load()

	// room for tag?
	if countSub(br.tagCount(), bw.tagCount())+len(b.tags) < 1 {
		return false
	}

	// room for data?
	nd := countSub(br.dataCount(), bw.dataCount()) + len(b.data)
	want := 2 + int(b.hdrsize) + nstk
	i := int(bw.dataCount() % uint32(len(b.data)))

		// and "created by $func in goroutine $n", remove the latter
		output := strings.ReplaceAll(string(buf), "in goroutine", "")
		nstk := strings.Count(output, "goroutine ")
		if n == nstk {
			break
		}
		if i >= 10 {
			t.Fatalf("NumGoroutine=%d, but found %d goroutines in stack dump: %s", n, nstk, buf)
		}
	}
}

func TestPingPongHog(t *testing.T) {
	if runtime.GOARCH == "wasm" {

// May run with m.p==nil, so write barriers are not allowed.
//
//go:nowritebarrier
func newosproc(mp *m) {
	stk := unsafe.Pointer(mp.g0.stack.hi)
	if false {
		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " id=", mp.id, " ostk=", &mp, "\n")
	}

	// Stack pointer must point inside stack area (as marked with MAP_STACK),
	// rather than at the top of it.
	param := tforkt{

func lwp_start(uintptr)

// May run with m.p==nil, so write barriers are not allowed.
//
//go:nowritebarrier
func newosproc(mp *m) {
	stk := unsafe.Pointer(mp.g0.stack.hi)
	if false {
		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " lwp_start=", abi.FuncPCABI0(lwp_start), " id=", mp.id, " ostk=", &mp, "\n")
	}

	var oset sigset
	sigprocmask(_SIG_SETMASK, &sigset_all, &oset)

	params := lwpparams{

		})
	}
}

// May run with m.p==nil, so write barriers are not allowed.
//
//go:nowritebarrier
func newosproc(mp *m) {
	stk := unsafe.Pointer(mp.g0.stack.hi)
	if false {
		print("newosproc stk=", stk, " m=", mp, " g=", mp.g0, " id=", mp.id, " ostk=", &mp, "\n")
	}

	var uc ucontextt
	getcontext(unsafe.Pointer(&uc))

	// _UC_SIGMASK does not seem to work here.