| // Copyright 2020 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. |
| |
| //go:build aix || darwin || dragonfly || freebsd || linux || netbsd || openbsd |
| // +build aix darwin dragonfly freebsd linux netbsd openbsd |
| |
| // TODO: test on Windows? |
| |
| package debug_test |
| |
| import ( |
| "runtime" |
| "runtime/debug" |
| "syscall" |
| "testing" |
| "unsafe" |
| ) |
| |
| func TestPanicOnFault(t *testing.T) { |
| if runtime.GOARCH == "s390x" { |
| t.Skip("s390x fault addresses are missing the low order bits") |
| } |
| if runtime.GOOS == "ios" { |
| t.Skip("iOS doesn't provide fault addresses") |
| } |
| m, err := syscall.Mmap(-1, 0, 0x1000, syscall.PROT_READ /* Note: no PROT_WRITE */, syscall.MAP_SHARED|syscall.MAP_ANON) |
| if err != nil { |
| t.Fatalf("can't map anonymous memory: %s", err) |
| } |
| defer syscall.Munmap(m) |
| old := debug.SetPanicOnFault(true) |
| defer debug.SetPanicOnFault(old) |
| const lowBits = 0x3e7 |
| defer func() { |
| r := recover() |
| if r == nil { |
| t.Fatalf("write did not fault") |
| } |
| type addressable interface { |
| Addr() uintptr |
| } |
| a, ok := r.(addressable) |
| if !ok { |
| t.Fatalf("fault does not contain address") |
| } |
| want := uintptr(unsafe.Pointer(&m[lowBits])) |
| got := a.Addr() |
| if got != want { |
| t.Fatalf("fault address %x, want %x", got, want) |
| } |
| }() |
| m[lowBits] = 1 // will fault |
| } |