| // $G $D/$F.go && $L $F.$A && (! ./$A.out || echo BUG: should fail) |
| |
| // Copyright 2009 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 |
| |
| import "unsafe" |
| |
| var dummy [512<<20]byte; // give us a big address space |
| type T struct { |
| x [256<<20] byte; |
| i int; |
| } |
| |
| var y *T; |
| var x = &y; |
| |
| func main() { |
| // the test only tests what we intend to test |
| // if dummy starts in the first 256 MB of memory. |
| // otherwise there might not be anything mapped |
| // at the address that might be accidentally |
| // dereferenced below. |
| if uintptr(unsafe.Pointer(&dummy)) > 256<<20 { |
| panic("dummy too far out"); |
| } |
| |
| // The problem here is that indexing into t with a large |
| // enough index can jump out of the unmapped section |
| // at the beginning of memory and into valid memory. |
| // We require the pointer dereference to check. |
| println((*x).i); // should crash |
| } |