diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index d360af52323..b783b3b3397 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -540,6 +540,10 @@ def _communicate_streams_posix(stdin, input_data, read_streams,
                 stdin.flush()
             except BrokenPipeError:
                 pass
+            except ValueError:
+                # ignore ValueError: I/O operation on closed file.
+                if not stdin.closed:
+                    raise
             if not input_data:
                 try:
                     stdin.close()
@@ -547,8 +551,14 @@ def _communicate_streams_posix(stdin, input_data, read_streams,
                     pass
                 stdin = None  # Don't register with selector
 
-        # Prepare input data
-        input_view = memoryview(input_data) if input_data else None
+        # Prepare input data - cast to bytes view for correct length tracking
+        if input_data:
+            if not isinstance(input_data, memoryview):
+                input_view = memoryview(input_data)
+            else:
+                input_view = input_data.cast("b")  # byte view required
+        else:
+            input_view = None
 
         with _PopenSelector() as selector:
             if stdin and input_data:
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index b0bc13e3d11..f91d1f3522f 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -2019,6 +2019,48 @@ def test_pipeline_with_input(self):
         self.assertEqual(result.stdout.strip(), '5')
         self.assertEqual(result.returncodes, [0, 0])
 
+    def test_pipeline_memoryview_input(self):
+        """Test pipeline with memoryview input (byte elements)"""
+        test_data = b"Hello, memoryview pipeline!"
+        mv = memoryview(test_data)
+        result = subprocess.run_pipeline(
+            [sys.executable, '-c',
+             'import sys; sys.stdout.buffer.write(sys.stdin.buffer.read())'],
+            [sys.executable, '-c',
+             'import sys; sys.stdout.buffer.write(sys.stdin.buffer.read().upper())'],
+            input=mv, capture_output=True
+        )
+        self.assertEqual(result.stdout, test_data.upper())
+        self.assertEqual(result.returncodes, [0, 0])
+
+    def test_pipeline_memoryview_input_nonbyte(self):
+        """Test pipeline with non-byte memoryview input (e.g., int32).
+
+        This tests the fix for gh-134453 where non-byte memoryviews
+        had incorrect length tracking on POSIX, causing data truncation.
+        """
+        import array
+        # Create an array of 32-bit integers large enough to trigger
+        # chunked writing behavior (> PIPE_BUF)
+        pipe_buf = getattr(select, 'PIPE_BUF', 512)
+        # Each 'i' element is 4 bytes, need more than pipe_buf bytes total
+        num_elements = (pipe_buf // 4) + 100
+        test_array = array.array('i', [0x41424344 for _ in range(num_elements)])
+        expected_bytes = test_array.tobytes()
+        mv = memoryview(test_array)
+
+        result = subprocess.run_pipeline(
+            [sys.executable, '-c',
+             'import sys; sys.stdout.buffer.write(sys.stdin.buffer.read())'],
+            [sys.executable, '-c',
+             'import sys; data = sys.stdin.buffer.read(); '
+             'sys.stdout.buffer.write(data)'],
+            input=mv, capture_output=True
+        )
+        self.assertEqual(result.stdout, expected_bytes,
+                         msg=f"{len(result.stdout)=} != {len(expected_bytes)=}")
+        self.assertEqual(result.returncodes, [0, 0])
+
     def test_pipeline_bytes_mode(self):
         """Test pipeline in binary mode"""
         result = subprocess.run_pipeline(