test: workaround SIGILL on issue11656 on aix

For some reason, aix sometimes executes the bogus function body. This
should never happen as it lives in a no-execute section. It might be
a transient permission blip as the heap grows.

Add a small function to cleanup and synchronize the icache before
jumping to the bogus function to ensure it causes a panic, not SIGILL.

Fixes #44583

Change-Id: Iadca62d82bfb70fc62088705dac42a880a1208fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/377314
Trust: Bryan Mills <bcmills@google.com>
Run-TryBot: Paul Murphy <murp@ibm.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Cherry Mui <cherryyz@google.com>

test/fixedbugs/issue11656.dir/asm.go

@@ -0,0 +1,10 @@
+// Copyright 2022 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 ppc64 || ppc64le
+// +build ppc64 ppc64le
+
+package main
+
+func syncIcache(p uintptr)

test/fixedbugs/issue11656.dir/asm_generic.go

@@ -0,0 +1,11 @@
+// Copyright 2022 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 !ppc64 && !ppc64le
+// +build !ppc64,!ppc64le
+
+package main
+
+func syncIcache(p uintptr) {
+}

test/fixedbugs/issue11656.dir/asm_ppc64.s

@@ -0,0 +1,13 @@
+// Copyright 2022 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.
+
+#include "textflag.h"
+
+// func syncIcache(p uintptr)
+TEXT main·syncIcache(SB), NOSPLIT|NOFRAME, $0-0
+	SYNC
+	MOVD (R3), R3
+	ICBI (R3)
+	ISYNC
+	RET

test/fixedbugs/issue11656.dir/asm_ppc64le.s

@@ -0,0 +1,13 @@
+// Copyright 2022 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.
+
+#include "textflag.h"
+
+// func syncIcache(p uintptr)
+TEXT main·syncIcache(SB), NOSPLIT|NOFRAME, $0-0
+	SYNC
+	MOVD (R3), R3
+	ICBI (R3)
+	ISYNC
+	RET

test/fixedbugs/issue11656.dir/issue11656.go

@@ -0,0 +1,75 @@
+// 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()
+}

test/fixedbugs/issue11656.go

@@ -1,89 +1,22 @@
-// run
+// runindir
 
-// Copyright 2015 The Go Authors. All rights reserved.
+// Copyright 2022 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.
 
+// Issue 11656: runtime: jump to bad PC missing good traceback
+
 // windows doesn't work, because Windows exception handling
 // delivers signals based on the current PC, and that current PC
 // doesn't go into the Go runtime.
-// +build !windows
 
 // wasm does not work, because the linear memory is not executable.
-// +build !wasm
 
 // This test doesn't work on gccgo/GoLLVM, because they will not find
 // any unwind information for the artificial function, and will not be
 // able to unwind past that point.
-// +build !gccgo
 
-package main
+//go:build !windows && !wasm && !gccgo
+// +build !windows,!wasm,!gccgo
 
-import (
+package ignored
-	"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))
-	fn()
-}