@@ -271,7 +271,6 @@ def test_access_parameter(self):
                     self.assertRaises(TypeError, m.write_byte, 0)
                     m.close()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     @unittest.skipIf(os.name == 'nt', 'trackfd not present on Windows')
     def test_trackfd_parameter(self):
         size = 64
@@ -307,7 +306,6 @@ def test_trackfd_parameter(self):
                 self.assertEqual(m.closed, True)
                 self.assertEqual(os.stat(TESTFN).st_size, size)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     @unittest.skipIf(os.name == 'nt', 'trackfd not present on Windows')
     def test_trackfd_neg1(self):
         size = 64
 
@@ -188,6 +188,8 @@ mod mmap {
         pos: AtomicCell<usize>, // relative to offset
         exports: AtomicCell<usize>,
         access: AccessMode,
+        #[cfg(unix)]
+        trackfd: bool,
     }
 
     impl PyMmap {
@@ -229,6 +231,8 @@ mod mmap {
         access: AccessMode,
         #[pyarg(any, default = 0)]
         offset: i64,
+        #[pyarg(any, default = true)]
+        trackfd: bool,
     }
 
     #[cfg(windows)]
@@ -364,6 +368,7 @@ mod mmap {
                 prot,
                 access,
                 offset,
+                trackfd,
                 ..
             } = args;
 
@@ -443,12 +448,17 @@ mod mmap {
             Ok(Self {
                 closed: AtomicCell::new(false),
                 mmap: PyMutex::new(Some(MmapObj::Mapped(mmap))),
-                fd: AtomicCell::new(fd.map_or(-1, |fd| fd.into_raw())),
+                fd: AtomicCell::new(if trackfd {
+                    fd.map_or(-1, |owned| owned.into_raw())
+                } else {
+                    -1
+                }),
                 offset,
                 size: AtomicCell::new(map_size),
                 pos: AtomicCell::new(0),
                 exports: AtomicCell::new(0),
                 access,
+                trackfd,
             })
         }
 
@@ -752,6 +762,11 @@ mod mmap {
                 return Err(vm.new_buffer_error("mmap can't resize with extant buffers exported."));
             }
 
+            #[cfg(unix)]
+            if !self.trackfd {
+                return Err(vm.new_value_error("mmap can't resize with trackfd=False."));
+            }
+
             if self.access == AccessMode::Write || self.access == AccessMode::Default {
                 return Ok(());
             }