Revert #167 to avoid race on Linux.

.github/workflows/test.yml

@@ -51,5 +51,10 @@ jobs:
       # Skip tests for 1.6 as we use modern Go.
       # If the main lib builds and tests pass on other versions, we are good.
       - if: ${{ matrix.go_version != '1.6.x' }}
-        name: Test
+        name: Single Test
         run: go test -v
+
+      # Run the tests again 100 times without verbose.
+      - if: ${{ matrix.go_version != '1.6.x' }}
+        name: Many Tests
+        run: go test -count=100 -timeout=10s

io_test.go

@@ -28,6 +28,8 @@ var glTestFdLock sync.Mutex
 //
 //nolint:paralleltest // Potential in (*os.File).Fd().
 func TestReadDeadline(t *testing.T) {
+	t.Skip("Disabling while investigating race.")
+
 	ptmx, success := prepare(t)
 
 	if err := ptmx.SetDeadline(time.Now().Add(timeout / 10)); err != nil {
@@ -57,6 +59,8 @@ func TestReadDeadline(t *testing.T) {
 //
 //nolint:paralleltest // Potential in (*os.File).Fd().
 func TestReadClose(t *testing.T) {
+	t.Skip("Disabling while investigating race.")
+
 	ptmx, success := prepare(t)
 
 	go func() {

ioctl.go

@@ -6,6 +6,11 @@ package pty
 import "os"
 
 func ioctl(f *os.File, cmd, ptr uintptr) error {
+	return ioctlInner(f.Fd(), cmd, ptr) // Fall back to blocking io.
+}
+
+// NOTE: Unused. Keeping for reference.
+func ioctlNonblock(f *os.File, cmd, ptr uintptr) error {
 	sc, e := f.SyscallConn()
 	if e != nil {
 		return ioctlInner(f.Fd(), cmd, ptr) // Fall back to blocking io (old behavior).