diff --git a/unix/shm_test.go b/unix/shm_test.go
new file mode 100644
index 00000000..b21bb439
--- /dev/null
+++ b/unix/shm_test.go
@@ -0,0 +1,64 @@
+// Copyright 2021 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.
+
+//go:build darwin
+// +build darwin
+
+package unix_test
+
+import (
+	"testing"
+
+	"golang.org/x/sys/unix"
+)
+
+func TestSysvSharedMemory(t *testing.T) {
+	// create ipc
+	id, err := unix.SysvShmGet(unix.IPC_PRIVATE, 1024, unix.IPC_CREAT|unix.IPC_EXCL|0o600)
+	if err != nil {
+		t.Fatalf("SysvShmGet: %v", err)
+	}
+	defer func() {
+		_, err := unix.SysvShmCtl(id, unix.IPC_RMID, nil)
+		if err != nil {
+			t.Errorf("Remove failed: %v", err)
+		}
+	}()
+
+	// attach
+	b1, err := unix.SysvShmAttach(id, 0, 0)
+	if err != nil {
+		t.Fatalf("Attach: %v", err)
+	}
+
+	if len(b1) != 1024 {
+		t.Fatalf("b1 len = %v, want 1024", len(b1))
+	}
+
+	b1[42] = 'x'
+
+	// attach again
+	b2, err := unix.SysvShmAttach(id, 0, 0)
+	if err != nil {
+		t.Fatalf("Attach: %v", err)
+	}
+
+	if len(b2) != 1024 {
+		t.Fatalf("b2 len = %v, want 1024", len(b1))
+	}
+
+	b2[43] = 'y'
+	if b2[42] != 'x' || b1[43] != 'y' {
+		t.Fatalf("shared memory isn't shared")
+	}
+
+	// detach
+	if err = unix.SysvShmDetach(b2); err != nil {
+		t.Fatalf("Detach: %v", err)
+	}
+
+	if b1[42] != 'x' || b1[43] != 'y' {
+		t.Fatalf("shared memory was invalidated")
+	}
+}
diff --git a/unix/syscall_unix.go b/unix/syscall_unix.go
index 9d3d4615..a0bcf4f9 100644
--- a/unix/syscall_unix.go
+++ b/unix/syscall_unix.go
@@ -447,8 +447,9 @@ func SysvShmAttach(id int, addr uintptr, flag int) ([]byte, error) {
 
 	_, err := SysvShmCtl(id, IPC_STAT, &info)
 	if err != nil {
-		// release the shared memory if we can't find the size; ignoring error
-		// here since there's nothing sensible we can return here
+		// release the shared memory if we can't find the size
+
+		// ignoring error from shmdt as there's nothing sensible to return here
 		shmdt(addr)
 		return nil, err
 	}
diff --git a/unix/syscall_unix_test.go b/unix/syscall_unix_test.go
index ea3a71be..2f672832 100644
--- a/unix/syscall_unix_test.go
+++ b/unix/syscall_unix_test.go
@@ -852,56 +852,6 @@ func TestRenameat(t *testing.T) {
 	}
 }
 
-func TestSysvSharedMemory(t *testing.T) {
-	// create ipc
-	id, err := unix.SysvShmGet(unix.IPC_PRIVATE, 1024, unix.IPC_CREAT|unix.IPC_EXCL|0o600)
-	if err != nil {
-		t.Fatalf("SysvShmGet: %v", err)
-	}
-	defer func() {
-		_, err := unix.SysvShmCtl(id, unix.IPC_RMID, nil)
-		if err != nil {
-			t.Errorf("Remove failed: %v", err)
-		}
-	}()
-
-	// attach
-	b1, err := unix.SysvShmAttach(id, 0, 0)
-	if err != nil {
-		t.Fatalf("Attach: %v", err)
-	}
-
-	if len(b1) != 1024 {
-		t.Fatalf("b1 len = %v, want 1024", len(b1))
-	}
-
-	b1[42] = 'x'
-
-	// attach again
-	b2, err := unix.SysvShmAttach(id, 0, 0)
-	if err != nil {
-		t.Fatalf("Attach: %v", err)
-	}
-
-	if len(b2) != 1024 {
-		t.Fatalf("b2 len = %v, want 1024", len(b1))
-	}
-
-	b2[43] = 'y'
-	if b2[42] != 'x' || b1[43] != 'y' {
-		t.Fatalf("shared memory isn't shared")
-	}
-
-	// detach
-	if err = unix.SysvShmDetach(b2); err != nil {
-		t.Fatalf("Detach: %v", err)
-	}
-
-	if b1[42] != 'x' || b1[43] != 'y' {
-		t.Fatalf("shared memory was invalidated")
-	}
-}
-
 func TestUtimesNanoAt(t *testing.T) {
 	defer chtmpdir(t)()