diff options
| -rw-r--r-- | src/runtime/signal_unix.go | 11 | ||||
| -rw-r--r-- | src/syscall/exec_unix_test.go | 45 |
2 files changed, 56 insertions, 0 deletions
diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go index dbac55c3d1..c7a6c2197c 100644 --- a/src/runtime/signal_unix.go +++ b/src/runtime/signal_unix.go @@ -360,6 +360,13 @@ func preemptM(mp *m) { // required). return } + + // On Darwin, don't try to preempt threads during exec. + // Issue #41702. + if GOOS == "darwin" { + execLock.rlock() + } + if atomic.Cas(&mp.signalPending, 0, 1) { // If multiple threads are preempting the same M, it may send many // signals to the same M such that it hardly make progress, causing @@ -368,6 +375,10 @@ func preemptM(mp *m) { // Only send a signal if there isn't already one pending. signalM(mp, sigPreempt) } + + if GOOS == "darwin" { + execLock.runlock() + } } // sigFetchG fetches the value of G safely when running in a signal handler. diff --git a/src/syscall/exec_unix_test.go b/src/syscall/exec_unix_test.go index 33614f5221..722534af78 100644 --- a/src/syscall/exec_unix_test.go +++ b/src/syscall/exec_unix_test.go @@ -9,11 +9,14 @@ package syscall_test import ( "internal/testenv" "io" + "math/rand" "os" "os/exec" "os/signal" + "runtime" "syscall" "testing" + "time" "unsafe" ) @@ -213,3 +216,45 @@ func TestForeground(t *testing.T) { signal.Reset() } + +// TestExec is for issue #41702. +func TestExec(t *testing.T) { + cmd := exec.Command(os.Args[0], "-test.run=TestExecHelper") + cmd.Env = append(os.Environ(), "GO_WANT_HELPER_PROCESS=2") + o, err := cmd.CombinedOutput() + if err != nil { + t.Errorf("%s\n%v", o, err) + } +} + +// TestExecHelper is used by TestExec. It does nothing by itself. +// In testing on macOS 10.14, this used to fail with +// "signal: illegal instruction" more than half the time. +func TestExecHelper(t *testing.T) { + if os.Getenv("GO_WANT_HELPER_PROCESS") != "2" { + return + } + + // We don't have to worry about restoring these values. + // We are in a child process that only runs this test, + // and we are going to call syscall.Exec anyhow. + runtime.GOMAXPROCS(50) + os.Setenv("GO_WANT_HELPER_PROCESS", "3") + + stop := time.Now().Add(time.Second) + for i := 0; i < 100; i++ { + go func(i int) { + r := rand.New(rand.NewSource(int64(i))) + for time.Now().Before(stop) { + r.Uint64() + } + }(i) + } + + time.Sleep(10 * time.Millisecond) + + argv := []string{os.Args[0], "-test.run=TestExecHelper"} + syscall.Exec(os.Args[0], argv, os.Environ()) + + t.Error("syscall.Exec returned") +} |