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// Copyright 2018 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.
// TODO: This test could be implemented on all (most?) UNIXes if we
// added syscall.Tgkill more widely.
// We skip all of these tests under race mode because our test thread
// spends all of its time in the race runtime, which isn't a safe
// point.
// +build ignore_for_gccgo
// +build amd64
// +build linux
// +build !race
package runtime_test
import (
"fmt"
"runtime"
"runtime/debug"
"sync/atomic"
"syscall"
"testing"
)
func startDebugCallWorker(t *testing.T) (g *runtime.G, after func()) {
// This can deadlock if there aren't enough threads or if a GC
// tries to interrupt an atomic loop (see issue #10958).
ogomaxprocs := runtime.GOMAXPROCS(2)
ogcpercent := debug.SetGCPercent(-1)
ready := make(chan *runtime.G)
var stop uint32
done := make(chan error)
go debugCallWorker(ready, &stop, done)
g = <-ready
return g, func() {
atomic.StoreUint32(&stop, 1)
err := <-done
if err != nil {
t.Fatal(err)
}
runtime.GOMAXPROCS(ogomaxprocs)
debug.SetGCPercent(ogcpercent)
}
}
func debugCallWorker(ready chan<- *runtime.G, stop *uint32, done chan<- error) {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
ready <- runtime.Getg()
x := 2
debugCallWorker2(stop, &x)
if x != 1 {
done <- fmt.Errorf("want x = 2, got %d; register pointer not adjusted?", x)
}
close(done)
}
func debugCallWorker2(stop *uint32, x *int) {
for atomic.LoadUint32(stop) == 0 {
// Strongly encourage x to live in a register so we
// can test pointer register adjustment.
*x++
}
*x = 1
}
func debugCallTKill(tid int) error {
return syscall.Tgkill(syscall.Getpid(), tid, syscall.SIGTRAP)
}
func TestDebugCall(t *testing.T) {
g, after := startDebugCallWorker(t)
defer after()
// Inject a call into the debugCallWorker goroutine and test
// basic argument and result passing.
var args struct {
x int
yRet int
}
fn := func(x int) (yRet int) {
return x + 1
}
args.x = 42
if _, err := runtime.InjectDebugCall(g, fn, &args, debugCallTKill); err != nil {
t.Fatal(err)
}
if args.yRet != 43 {
t.Fatalf("want 43, got %d", args.yRet)
}
}
func TestDebugCallLarge(t *testing.T) {
g, after := startDebugCallWorker(t)
defer after()
// Inject a call with a large call frame.
const N = 128
var args struct {
in [N]int
out [N]int
}
fn := func(in [N]int) (out [N]int) {
for i := range in {
out[i] = in[i] + 1
}
return
}
var want [N]int
for i := range args.in {
args.in[i] = i
want[i] = i + 1
}
if _, err := runtime.InjectDebugCall(g, fn, &args, debugCallTKill); err != nil {
t.Fatal(err)
}
if want != args.out {
t.Fatalf("want %v, got %v", want, args.out)
}
}
func TestDebugCallGC(t *testing.T) {
g, after := startDebugCallWorker(t)
defer after()
// Inject a call that performs a GC.
if _, err := runtime.InjectDebugCall(g, runtime.GC, nil, debugCallTKill); err != nil {
t.Fatal(err)
}
}
func TestDebugCallGrowStack(t *testing.T) {
g, after := startDebugCallWorker(t)
defer after()
// Inject a call that grows the stack. debugCallWorker checks
// for stack pointer breakage.
if _, err := runtime.InjectDebugCall(g, func() { growStack(nil) }, nil, debugCallTKill); err != nil {
t.Fatal(err)
}
}
//go:nosplit
func debugCallUnsafePointWorker(gpp **runtime.G, ready, stop *uint32) {
// The nosplit causes this function to not contain safe-points
// except at calls.
runtime.LockOSThread()
defer runtime.UnlockOSThread()
*gpp = runtime.Getg()
for atomic.LoadUint32(stop) == 0 {
atomic.StoreUint32(ready, 1)
}
}
func TestDebugCallUnsafePoint(t *testing.T) {
// This can deadlock if there aren't enough threads or if a GC
// tries to interrupt an atomic loop (see issue #10958).
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
defer debug.SetGCPercent(debug.SetGCPercent(-1))
// Test that the runtime refuses call injection at unsafe points.
var g *runtime.G
var ready, stop uint32
defer atomic.StoreUint32(&stop, 1)
go debugCallUnsafePointWorker(&g, &ready, &stop)
for atomic.LoadUint32(&ready) == 0 {
runtime.Gosched()
}
_, err := runtime.InjectDebugCall(g, func() {}, nil, debugCallTKill)
if msg := "call not at safe point"; err == nil || err.Error() != msg {
t.Fatalf("want %q, got %s", msg, err)
}
}
func TestDebugCallPanic(t *testing.T) {
// This can deadlock if there aren't enough threads.
defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(2))
ready := make(chan *runtime.G)
var stop uint32
defer atomic.StoreUint32(&stop, 1)
go func() {
runtime.LockOSThread()
defer runtime.UnlockOSThread()
ready <- runtime.Getg()
for atomic.LoadUint32(&stop) == 0 {
}
}()
g := <-ready
p, err := runtime.InjectDebugCall(g, func() { panic("test") }, nil, debugCallTKill)
if err != nil {
t.Fatal(err)
}
if ps, ok := p.(string); !ok || ps != "test" {
t.Fatalf("wanted panic %v, got %v", "test", p)
}
}
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