Source file src/runtime/crash_unix_test.go

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  //go:build unix
     6  
     7  package runtime_test
     8  
     9  import (
    10  	"bytes"
    11  	"internal/testenv"
    12  	"io"
    13  	"os"
    14  	"os/exec"
    15  	"runtime"
    16  	"runtime/debug"
    17  	"sync"
    18  	"syscall"
    19  	"testing"
    20  	"time"
    21  	"unsafe"
    22  )
    23  
    24  func init() {
    25  	if runtime.Sigisblocked(int(syscall.SIGQUIT)) {
    26  		// We can't use SIGQUIT to kill subprocesses because
    27  		// it's blocked. Use SIGKILL instead. See issue
    28  		// #19196 for an example of when this happens.
    29  		testenv.Sigquit = syscall.SIGKILL
    30  	}
    31  }
    32  
    33  func TestBadOpen(t *testing.T) {
    34  	// make sure we get the correct error code if open fails. Same for
    35  	// read/write/close on the resulting -1 fd. See issue 10052.
    36  	nonfile := []byte("/notreallyafile")
    37  	fd := runtime.Open(&nonfile[0], 0, 0)
    38  	if fd != -1 {
    39  		t.Errorf("open(%q)=%d, want -1", nonfile, fd)
    40  	}
    41  	var buf [32]byte
    42  	r := runtime.Read(-1, unsafe.Pointer(&buf[0]), int32(len(buf)))
    43  	if got, want := r, -int32(syscall.EBADF); got != want {
    44  		t.Errorf("read()=%d, want %d", got, want)
    45  	}
    46  	w := runtime.Write(^uintptr(0), unsafe.Pointer(&buf[0]), int32(len(buf)))
    47  	if got, want := w, -int32(syscall.EBADF); got != want {
    48  		t.Errorf("write()=%d, want %d", got, want)
    49  	}
    50  	c := runtime.Close(-1)
    51  	if c != -1 {
    52  		t.Errorf("close()=%d, want -1", c)
    53  	}
    54  }
    55  
    56  func TestCrashDumpsAllThreads(t *testing.T) {
    57  	if *flagQuick {
    58  		t.Skip("-quick")
    59  	}
    60  
    61  	switch runtime.GOOS {
    62  	case "darwin", "dragonfly", "freebsd", "linux", "netbsd", "openbsd", "illumos", "solaris":
    63  	default:
    64  		t.Skipf("skipping; not supported on %v", runtime.GOOS)
    65  	}
    66  
    67  	if runtime.GOOS == "openbsd" && (runtime.GOARCH == "arm" || runtime.GOARCH == "mips64") {
    68  		// This may be ncpu < 2 related...
    69  		t.Skipf("skipping; test fails on %s/%s - see issue #42464", runtime.GOOS, runtime.GOARCH)
    70  	}
    71  
    72  	if runtime.Sigisblocked(int(syscall.SIGQUIT)) {
    73  		t.Skip("skipping; SIGQUIT is blocked, see golang.org/issue/19196")
    74  	}
    75  
    76  	testenv.MustHaveGoBuild(t)
    77  
    78  	exe, err := buildTestProg(t, "testprog")
    79  	if err != nil {
    80  		t.Fatal(err)
    81  	}
    82  
    83  	cmd := exec.Command(exe, "CrashDumpsAllThreads")
    84  	cmd = testenv.CleanCmdEnv(cmd)
    85  	cmd.Env = append(cmd.Env,
    86  		"GOTRACEBACK=crash",
    87  		// Set GOGC=off. Because of golang.org/issue/10958, the tight
    88  		// loops in the test program are not preemptible. If GC kicks
    89  		// in, it may lock up and prevent main from saying it's ready.
    90  		"GOGC=off",
    91  		// Set GODEBUG=asyncpreemptoff=1. If a thread is preempted
    92  		// when it receives SIGQUIT, it won't show the expected
    93  		// stack trace. See issue 35356.
    94  		"GODEBUG=asyncpreemptoff=1",
    95  	)
    96  
    97  	var outbuf bytes.Buffer
    98  	cmd.Stdout = &outbuf
    99  	cmd.Stderr = &outbuf
   100  
   101  	rp, wp, err := os.Pipe()
   102  	if err != nil {
   103  		t.Fatal(err)
   104  	}
   105  	defer rp.Close()
   106  
   107  	cmd.ExtraFiles = []*os.File{wp}
   108  
   109  	if err := cmd.Start(); err != nil {
   110  		wp.Close()
   111  		t.Fatalf("starting program: %v", err)
   112  	}
   113  
   114  	if err := wp.Close(); err != nil {
   115  		t.Logf("closing write pipe: %v", err)
   116  	}
   117  	if _, err := rp.Read(make([]byte, 1)); err != nil {
   118  		t.Fatalf("reading from pipe: %v", err)
   119  	}
   120  
   121  	if err := cmd.Process.Signal(syscall.SIGQUIT); err != nil {
   122  		t.Fatalf("signal: %v", err)
   123  	}
   124  
   125  	// No point in checking the error return from Wait--we expect
   126  	// it to fail.
   127  	cmd.Wait()
   128  
   129  	// We want to see a stack trace for each thread.
   130  	// Before https://golang.org/cl/2811 running threads would say
   131  	// "goroutine running on other thread; stack unavailable".
   132  	out := outbuf.Bytes()
   133  	n := bytes.Count(out, []byte("main.crashDumpsAllThreadsLoop("))
   134  	if n != 4 {
   135  		t.Errorf("found %d instances of main.crashDumpsAllThreadsLoop; expected 4", n)
   136  		t.Logf("%s", out)
   137  	}
   138  }
   139  
   140  func TestPanicSystemstack(t *testing.T) {
   141  	// Test that GOTRACEBACK=crash prints both the system and user
   142  	// stack of other threads.
   143  
   144  	// The GOTRACEBACK=crash handler takes 0.1 seconds even if
   145  	// it's not writing a core file and potentially much longer if
   146  	// it is. Skip in short mode.
   147  	if testing.Short() {
   148  		t.Skip("Skipping in short mode (GOTRACEBACK=crash is slow)")
   149  	}
   150  
   151  	if runtime.Sigisblocked(int(syscall.SIGQUIT)) {
   152  		t.Skip("skipping; SIGQUIT is blocked, see golang.org/issue/19196")
   153  	}
   154  
   155  	t.Parallel()
   156  	cmd := exec.Command(os.Args[0], "testPanicSystemstackInternal")
   157  	cmd = testenv.CleanCmdEnv(cmd)
   158  	cmd.Env = append(cmd.Env, "GOTRACEBACK=crash")
   159  	pr, pw, err := os.Pipe()
   160  	if err != nil {
   161  		t.Fatal("creating pipe: ", err)
   162  	}
   163  	cmd.Stderr = pw
   164  	if err := cmd.Start(); err != nil {
   165  		t.Fatal("starting command: ", err)
   166  	}
   167  	defer cmd.Process.Wait()
   168  	defer cmd.Process.Kill()
   169  	if err := pw.Close(); err != nil {
   170  		t.Log("closing write pipe: ", err)
   171  	}
   172  	defer pr.Close()
   173  
   174  	// Wait for "x\nx\n" to indicate almost-readiness.
   175  	buf := make([]byte, 4)
   176  	_, err = io.ReadFull(pr, buf)
   177  	if err != nil || string(buf) != "x\nx\n" {
   178  		t.Fatal("subprocess failed; output:\n", string(buf))
   179  	}
   180  
   181  	// The child blockers print "x\n" and then block on a lock. Receiving
   182  	// those bytes only indicates that the child is _about to block_. Since
   183  	// we don't have a way to know when it is fully blocked, sleep a bit to
   184  	// make us less likely to lose the race and signal before the child
   185  	// blocks.
   186  	time.Sleep(100 * time.Millisecond)
   187  
   188  	// Send SIGQUIT.
   189  	if err := cmd.Process.Signal(syscall.SIGQUIT); err != nil {
   190  		t.Fatal("signaling subprocess: ", err)
   191  	}
   192  
   193  	// Get traceback.
   194  	tb, err := io.ReadAll(pr)
   195  	if err != nil {
   196  		t.Fatal("reading traceback from pipe: ", err)
   197  	}
   198  
   199  	// Traceback should have two testPanicSystemstackInternal's
   200  	// and two blockOnSystemStackInternal's.
   201  	if bytes.Count(tb, []byte("testPanicSystemstackInternal")) != 2 {
   202  		t.Fatal("traceback missing user stack:\n", string(tb))
   203  	} else if bytes.Count(tb, []byte("blockOnSystemStackInternal")) != 2 {
   204  		t.Fatal("traceback missing system stack:\n", string(tb))
   205  	}
   206  }
   207  
   208  func init() {
   209  	if len(os.Args) >= 2 && os.Args[1] == "testPanicSystemstackInternal" {
   210  		// Complete any in-flight GCs and disable future ones. We're going to
   211  		// block goroutines on runtime locks, which aren't ever preemptible for the
   212  		// GC to scan them.
   213  		runtime.GC()
   214  		debug.SetGCPercent(-1)
   215  		// Get two threads running on the system stack with
   216  		// something recognizable in the stack trace.
   217  		runtime.GOMAXPROCS(2)
   218  		go testPanicSystemstackInternal()
   219  		testPanicSystemstackInternal()
   220  	}
   221  }
   222  
   223  func testPanicSystemstackInternal() {
   224  	runtime.BlockOnSystemStack()
   225  	os.Exit(1) // Should be unreachable.
   226  }
   227  
   228  func TestSignalExitStatus(t *testing.T) {
   229  	testenv.MustHaveGoBuild(t)
   230  	exe, err := buildTestProg(t, "testprog")
   231  	if err != nil {
   232  		t.Fatal(err)
   233  	}
   234  	err = testenv.CleanCmdEnv(exec.Command(exe, "SignalExitStatus")).Run()
   235  	if err == nil {
   236  		t.Error("test program succeeded unexpectedly")
   237  	} else if ee, ok := err.(*exec.ExitError); !ok {
   238  		t.Errorf("error (%v) has type %T; expected exec.ExitError", err, err)
   239  	} else if ws, ok := ee.Sys().(syscall.WaitStatus); !ok {
   240  		t.Errorf("error.Sys (%v) has type %T; expected syscall.WaitStatus", ee.Sys(), ee.Sys())
   241  	} else if !ws.Signaled() || ws.Signal() != syscall.SIGTERM {
   242  		t.Errorf("got %v; expected SIGTERM", ee)
   243  	}
   244  }
   245  
   246  func TestSignalIgnoreSIGTRAP(t *testing.T) {
   247  	if runtime.GOOS == "openbsd" {
   248  		testenv.SkipFlaky(t, 49725)
   249  	}
   250  
   251  	output := runTestProg(t, "testprognet", "SignalIgnoreSIGTRAP")
   252  	want := "OK\n"
   253  	if output != want {
   254  		t.Fatalf("want %s, got %s\n", want, output)
   255  	}
   256  }
   257  
   258  func TestSignalDuringExec(t *testing.T) {
   259  	switch runtime.GOOS {
   260  	case "darwin", "dragonfly", "freebsd", "linux", "netbsd", "openbsd":
   261  	default:
   262  		t.Skipf("skipping test on %s", runtime.GOOS)
   263  	}
   264  	output := runTestProg(t, "testprognet", "SignalDuringExec")
   265  	want := "OK\n"
   266  	if output != want {
   267  		t.Fatalf("want %s, got %s\n", want, output)
   268  	}
   269  }
   270  
   271  func TestSignalM(t *testing.T) {
   272  	r, w, errno := runtime.Pipe()
   273  	if errno != 0 {
   274  		t.Fatal(syscall.Errno(errno))
   275  	}
   276  	defer func() {
   277  		runtime.Close(r)
   278  		runtime.Close(w)
   279  	}()
   280  	runtime.Closeonexec(r)
   281  	runtime.Closeonexec(w)
   282  
   283  	var want, got int64
   284  	var wg sync.WaitGroup
   285  	ready := make(chan *runtime.M)
   286  	wg.Add(1)
   287  	go func() {
   288  		runtime.LockOSThread()
   289  		want, got = runtime.WaitForSigusr1(r, w, func(mp *runtime.M) {
   290  			ready <- mp
   291  		})
   292  		runtime.UnlockOSThread()
   293  		wg.Done()
   294  	}()
   295  	waitingM := <-ready
   296  	runtime.SendSigusr1(waitingM)
   297  
   298  	timer := time.AfterFunc(time.Second, func() {
   299  		// Write 1 to tell WaitForSigusr1 that we timed out.
   300  		bw := byte(1)
   301  		if n := runtime.Write(uintptr(w), unsafe.Pointer(&bw), 1); n != 1 {
   302  			t.Errorf("pipe write failed: %d", n)
   303  		}
   304  	})
   305  	defer timer.Stop()
   306  
   307  	wg.Wait()
   308  	if got == -1 {
   309  		t.Fatal("signalM signal not received")
   310  	} else if want != got {
   311  		t.Fatalf("signal sent to M %d, but received on M %d", want, got)
   312  	}
   313  }
   314  

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