mirror of
https://github.com/golang/go
synced 2024-11-18 07:04:52 -07:00
64c134f90f
We need to make sure that there's no possible faulting instruction between a VarDef and that variable being fully initialized. If there was, then anything scanning the stack during the handling of that fault will see a live but uninitialized variable on the stack. If we have: NilCheck p VarDef x x = *p We can't rewrite that to VarDef x NilCheck p x = *p Particularly, even though *p faults on p==nil, we still have to do the explicit nil check before the VarDef. Fixes #32288 Change-Id: Ib8b88e6a5af3bf6f238ff5491ac86f53f3cf9fc9 Reviewed-on: https://go-review.googlesource.com/c/go/+/179239 Run-TryBot: Keith Randall <khr@golang.org> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com> Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
49 lines
809 B
Go
49 lines
809 B
Go
// run
|
|
|
|
// Copyright 2019 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package main
|
|
|
|
type T struct {
|
|
s [1]string
|
|
pad [16]uintptr
|
|
}
|
|
|
|
//go:noinline
|
|
func f(t *int, p *int) []T {
|
|
var res []T
|
|
for {
|
|
var e *T
|
|
res = append(res, *e)
|
|
}
|
|
}
|
|
|
|
func main() {
|
|
defer func() {
|
|
useStack(100) // force a stack copy
|
|
// We're expecting a panic.
|
|
// The bug in this issue causes a throw, which this recover() will not squash.
|
|
recover()
|
|
}()
|
|
junk() // fill the stack with invalid pointers
|
|
f(nil, nil)
|
|
}
|
|
|
|
func useStack(n int) {
|
|
if n == 0 {
|
|
return
|
|
}
|
|
useStack(n - 1)
|
|
}
|
|
|
|
//go:noinline
|
|
func junk() uintptr {
|
|
var a [128]uintptr // 1k of bad pointers on the stack
|
|
for i := range a {
|
|
a[i] = 0xaa
|
|
}
|
|
return a[12]
|
|
}
|