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// Copyright 2015 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 (
"encoding/binary"
"runtime"
"runtime/debug"
"unsafe"
)
func main() {
debug.SetPanicOnFault(true)
defer func() {
if err := recover(); err == nil {
panic("not panicking")
}
pc, _, _, _ := runtime.Caller(10)
f := runtime.FuncForPC(pc)
if f == nil || f.Name() != "main.f" {
if f == nil {
println("no func for ", unsafe.Pointer(pc))
} else {
println("found func:", f.Name())
}
panic("cannot find main.f on stack")
}
}()
f(20)
}
func f(n int) {
if n > 0 {
f(n - 1)
}
var f struct {
x uintptr
}
// We want to force a seg fault, to get a crash at a PC value != 0.
// Not all systems make the data section non-executable.
ill := make([]byte, 64)
switch runtime.GOARCH {
case "386", "amd64":
ill = append(ill[:0], 0x89, 0x04, 0x25, 0x00, 0x00, 0x00, 0x00) // MOVL AX, 0
case "arm":
binary.LittleEndian.PutUint32(ill[0:4], 0xe3a00000) // MOVW $0, R0
binary.LittleEndian.PutUint32(ill[4:8], 0xe5800000) // MOVW R0, (R0)
case "arm64":
binary.LittleEndian.PutUint32(ill, 0xf90003ff) // MOVD ZR, (ZR)
case "ppc64":
binary.BigEndian.PutUint32(ill, 0xf8000000) // MOVD R0, (R0)
case "ppc64le":
binary.LittleEndian.PutUint32(ill, 0xf8000000) // MOVD R0, (R0)
case "mips", "mips64":
binary.BigEndian.PutUint32(ill, 0xfc000000) // MOVV R0, (R0)
case "mipsle", "mips64le":
binary.LittleEndian.PutUint32(ill, 0xfc000000) // MOVV R0, (R0)
case "s390x":
ill = append(ill[:0], 0xa7, 0x09, 0x00, 0x00) // MOVD $0, R0
ill = append(ill, 0xe3, 0x00, 0x00, 0x00, 0x00, 0x24) // MOVD R0, (R0)
case "riscv64":
binary.LittleEndian.PutUint32(ill, 0x00003023) // MOV X0, (X0)
default:
// Just leave it as 0 and hope for the best.
}
f.x = uintptr(unsafe.Pointer(&ill[0]))
p := &f
fn := *(*func())(unsafe.Pointer(&p))
syncIcache(f.x)
fn()
}
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