return true
			})
		}
	case EventExperimental:
		r := e.Experimental()
		fmt.Fprintf(&sb, " Name=%s ArgNames=%v Args=%v", r.Name, r.ArgNames, r.Args)
	}
	if stk := e.Stack(); stk != NoStack {
		fmt.Fprintln(&sb)
		fmt.Fprintln(&sb, "Stack=")
		stk.Frames(func(f StackFrame) bool {
			fmt.Fprintf(&sb, "\t%s @ 0x%x\n", f.Func, f.PC)
			fmt.Fprintf(&sb, "\t\t%s:%d\n", f.File, f.Line)
			return true
		})
	}

				p := *(*uintptr)(unsafe.Pointer(b + i))
				if p != 0 {
					if obj, span, objIndex := findObject(p, b, i); obj != 0 {
						greyobject(obj, b, i, span, gcw, objIndex)
					} else if stk != nil && p >= stk.stack.lo && p < stk.stack.hi {
						stk.putPtr(p, false)
					}
				}
			}
			bits >>= 1
			i += goarch.PtrSize
		}
	}
}

// scanobject scans the object starting at b, adding pointers to gcw.

		s = &schedContext{M: m, P: trace.NoProc, G: trace.NoGoroutine}
		v.ms[m] = s
		return s
	}
	return s
}

func checkStack(e *errAccumulator, stk trace.Stack) {
	// Check for non-empty values, but we also check for crashes due to incorrect validation.
	i := 0
	stk.Frames(func(f trace.StackFrame) bool {
		if i == 0 {
			// Allow for one fully zero stack.
			//
			// TODO(mknyszek): Investigate why that happens.

		// This should be impossible but let's be safe.
		return fmt.Errorf("couldn't add strings: %w", addErr)
	}

	it.evt.strings.compactify()

	// Convert stacks.
	for id, stk := range pr.Stacks {
		evt.stacks.insert(stackID(id), stack{pcs: stk})
	}

	// OPT(dh): if we could share the frame type between this package and
	// oldtrace we wouldn't have to copy the map.
	for pc, f := range pr.PCs {
		evt.pcs[pc] = frame{

func validateStackStrings(
	stacks *dataTable[stackID, stack],
	strings *dataTable[stringID, string],
	frames map[uint64]frame,
) error {
	var err error
	stacks.forEach(func(id stackID, stk stack) bool {
		for _, pc := range stk.pcs {
			frame, ok := frames[pc]
			if !ok {
				err = fmt.Errorf("found unknown pc %x for stack %d", pc, id)
				return false
			}
			_, ok = strings.get(frame.funcID)
			if !ok {

			// This root frame will be identical for all transitions on this
			// goroutine, because it represents its immutable start point.
			if g.Name == "" {
				stk := st.Stack
				if stk != NoStack {
					var frame StackFrame
					var ok bool
					stk.Frames(func(f StackFrame) bool {
						frame = f
						ok = true
						return true
					})
					if ok {
						// NB: this PC won't actually be consistent for

		hi = frame.sp + maxExpand
	}
	// And don't go outside the stack bounds.
	if lo < stk.lo {
		lo = stk.lo
	}
	if hi > stk.hi {
		hi = stk.hi
	}

	// Print the hex dump.
	print("stack: frame={sp:", hex(frame.sp), ", fp:", hex(frame.fp), "} stack=[", hex(stk.lo), ",", hex(stk.hi), ")\n")
	hexdumpWords(lo, hi, func(p uintptr) byte {
		switch p {
		case frame.fp:
			return '>'

					{"internal/poll.(*FD).Read", 0},
					{"os.(*File).read", 0},
					{"os.(*File).Read", 0},
					{"main.main.func11", 0},
				}},
			}...)
		}
		stackMatches := func(stk trace.Stack, frames []frame) bool {
			i := 0
			match := true
			stk.Frames(func(f trace.StackFrame) bool {
				if f.Func != frames[i].fn {
					match = false
					return false
				}

}

//go:noinline
func TracebackSystemstack(stk []uintptr, i int) int {
	if i == 0 {
		pc, sp := getcallerpc(), getcallersp()
		var u unwinder
		u.initAt(pc, sp, 0, getg(), unwindJumpStack) // Don't ignore errors, for testing
		return tracebackPCs(&u, 0, stk)
	}
	n := 0
	systemstack(func() {
		n = TracebackSystemstack(stk, i-1)
	})
	return n
}

func KeepNArenaHints(n int) {

}

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
			n := len(buf)
			n--