diff --git a/unix/syscall_netbsd_test.go b/unix/syscall_netbsd_test.go
index d26fe314c..cd22c94d1 100644
--- a/unix/syscall_netbsd_test.go
+++ b/unix/syscall_netbsd_test.go
@@ -38,7 +38,12 @@ func TestIoctlPtmget(t *testing.T) {
 		t.Fatalf("IoctlGetPtmget: %v\n", err)
 	}
 
-	t.Logf("sfd = %v, ptsname = %v", ptm.Sfd, unix.ByteSliceToString(ptm.Sn[:]))
+	ptsname := unix.ByteSliceToString(ptm.Sn[:])
+	if ptsname == "" {
+		t.Fatalf("IoctlGetPtmget: ptsname is empty string\n")
+	}
+
+	t.Logf("sfd = %v, ptsname = %v", ptm.Sfd, ptsname)
 }
 
 func TestStatvfs(t *testing.T) {
diff --git a/unix/ztypes_netbsd_386.go b/unix/ztypes_netbsd_386.go
index f22e7947d..fd767f29b 100644
--- a/unix/ztypes_netbsd_386.go
+++ b/unix/ztypes_netbsd_386.go
@@ -438,8 +438,8 @@ type Winsize struct {
 type Ptmget struct {
 	Cfd int32
 	Sfd int32
-	Cn  [1024]byte
-	Sn  [1024]byte
+	Cn  [16]byte
+	Sn  [16]byte
 }
 
 const (
diff --git a/unix/ztypes_netbsd_amd64.go b/unix/ztypes_netbsd_amd64.go
index 066a7d83d..fd230f906 100644
--- a/unix/ztypes_netbsd_amd64.go
+++ b/unix/ztypes_netbsd_amd64.go
@@ -446,8 +446,8 @@ type Winsize struct {
 type Ptmget struct {
 	Cfd int32
 	Sfd int32
-	Cn  [1024]byte
-	Sn  [1024]byte
+	Cn  [16]byte
+	Sn  [16]byte
 }
 
 const (
diff --git a/unix/ztypes_netbsd_arm64.go b/unix/ztypes_netbsd_arm64.go
index 16085d3bb..cc955b261 100644
--- a/unix/ztypes_netbsd_arm64.go
+++ b/unix/ztypes_netbsd_arm64.go
@@ -446,8 +446,8 @@ type Winsize struct {
 type Ptmget struct {
 	Cfd int32
 	Sfd int32
-	Cn  [1024]byte
-	Sn  [1024]byte
+	Cn  [16]byte
+	Sn  [16]byte
 }
 
 const (