@@ -1270,8 +1270,8 @@ class BlockingLockFile(LockFile):
     specified timeout.
 
     :note:
-        If the directory containing the lock was removed, an exception will be raised
-        during the blocking period, preventing hangs as the lock can never be obtained.
+        Only an existing lock causes retries. Other errors, including a removed or
+        unwritable parent directory, are raised immediately.
     """
 
     __slots__ = ("_check_interval", "_max_block_time")
@@ -1297,7 +1297,7 @@ def __init__(
 
     def _obtain_lock(self) -> None:
         """This method blocks until it obtained the lock, or raises :exc:`IOError` if it
-        ran out of time or if the parent directory was not available anymore.
+        ran out of time or lock creation failed for a reason other than an existing lock.
 
         If this method returns, you are guaranteed to own the lock.
         """
@@ -1307,8 +1307,12 @@ def _obtain_lock(self) -> None:
             try:
                 super()._obtain_lock()
             except OSError as e:
-                # synity check: if the directory leading to the lockfile is not
-                # readable anymore, raise an exception
+                # LockFile retains the creation error as the cause of its OSError.
+                # Only an existing lock is contention; other errors must not be retried.
+                if not isinstance(e.__cause__, FileExistsError):
+                    raise
+
+                # Abort if the directory containing the existing lock has disappeared.
                 curtime = time.time()
                 if not osp.isdir(osp.dirname(self._lock_file_path()) or osp.curdir):
                     msg = "Directory containing the lockfile %r was not readable anymore after waiting %g seconds" % (
 
@@ -3,6 +3,7 @@
 # This module is part of GitPython and is released under the
 # 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/
 
+import errno
 import glob
 import io
 import os
@@ -17,7 +18,7 @@
 from git import GitConfigParser, Repo
 from git.compat import defenc
 from git.config import _OMD, cp
-from git.util import cwd, rmfile
+from git.util import BlockingLockFile, cwd, rmfile
 from test.lib import SkipTest, TestCase, fixture_path, with_rw_directory
 
 _tc_lock_fpaths = osp.join(osp.dirname(__file__), "fixtures/*.lock")
@@ -28,6 +29,23 @@ def _rm_lock_files():
         rmfile(lfp)
 
 
+@pytest.mark.skipif(sys.platform == "win32", reason="Lock creation uses CreateFileW on Windows")
+@pytest.mark.parametrize("error_number", [errno.EACCES, errno.ENOENT])
+def test_blocking_config_lock_propagates_non_contention_errors(tmp_path, monkeypatch, error_number):
+    monkeypatch.chdir(tmp_path)
+    monkeypatch.setattr(GitConfigParser, "t_lock", BlockingLockFile)
+    error = OSError(error_number, os.strerror(error_number), "config.lock")
+    with mock.patch.object(os, "open", side_effect=error) as open_lock:
+        with mock.patch.object(time, "sleep", side_effect=AssertionError("Must not retry")) as sleep:
+            with pytest.raises(OSError) as exc_info:
+                GitConfigParser("config", read_only=False)
+            sleep.assert_not_called()
+        open_lock.assert_called_once()
+    assert exc_info.value.__cause__ is error
+    assert str(exc_info.value) == str(error)
+    assert not (tmp_path / "config.lock").exists()
+
+
 class TestBase(TestCase):
     def setUp(self):
         _rm_lock_files()
 
@@ -4,7 +4,7 @@
 # 3-Clause BSD License: https://opensource.org/license/bsd-3-clause/
 
 import ast
-from datetime import datetime
+import errno
 import os
 import pathlib
 import pickle
@@ -14,6 +14,7 @@
 import tempfile
 import threading
 import time
+from datetime import datetime
 from unittest import SkipTest, mock
 
 import ddt
@@ -37,12 +38,11 @@
     LockFile,
     cygpath,
     decygpath,
-    is_cygwin_git,
     get_user_id,
+    is_cygwin_git,
     remove_password_if_present,
     rmtree,
 )
-
 from test.lib import TestBase, requires_symlinks, with_rw_repo
 
 
@@ -917,5 +917,67 @@ def test_blocking_relative_lock_reports_timeout(tmp_path, monkeypatch, path_type
 
 def test_blocking_lock_still_rejects_missing_directory(tmp_path):
     waiter = BlockingLockFile(tmp_path / "missing" / "resource")
-    with pytest.raises(OSError, match="Directory containing the lockfile"):
-        waiter._obtain_lock()
+    with mock.patch.object(time, "sleep", side_effect=AssertionError("Must not retry")) as sleep:
+        with pytest.raises(OSError) as exc_info:
+            waiter._obtain_lock()
+        sleep.assert_not_called()
+    assert isinstance(exc_info.value.__cause__, FileNotFoundError)
+    assert not waiter._has_lock()
+
+
+@pytest.mark.skipif(sys.platform == "win32", reason="Lock creation uses CreateFileW on Windows")
+@pytest.mark.parametrize(
+    "error_number", [errno.EACCES, errno.ENOENT, errno.ENOTDIR, errno.EROFS, errno.ENOSPC, errno.EIO]
+)
+@pytest.mark.parametrize("path_type", [str, pathlib.Path])
+@pytest.mark.parametrize("relative", [True, False])
+def test_blocking_lock_propagates_non_contention_errors(tmp_path, monkeypatch, error_number, path_type, relative):
+    monkeypatch.chdir(tmp_path)
+    path = path_type("resource" if relative else tmp_path / "resource")
+    waiter = BlockingLockFile(path)
+    error = OSError(error_number, os.strerror(error_number), waiter._lock_file_path())
+    with mock.patch.object(os, "open", side_effect=error) as open_lock:
+        with mock.patch.object(time, "sleep", side_effect=AssertionError("Must not retry")) as sleep:
+            with pytest.raises(OSError) as exc_info:
+                waiter._obtain_lock()
+            sleep.assert_not_called()
+        open_lock.assert_called_once()
+    assert exc_info.value.__cause__ is error
+    assert str(exc_info.value) == str(error)
+    assert not waiter._has_lock()
+    assert not os.path.lexists(waiter._lock_file_path())
+
+
+@pytest.mark.skipif(os.name != "posix", reason="Directory write permissions require POSIX")
+@pytest.mark.parametrize("path_type", [str, pathlib.Path])
+def test_blocking_relative_lock_rejects_unwritable_cwd(tmp_path, monkeypatch, path_type):
+    monkeypatch.chdir(tmp_path)
+    original_mode = tmp_path.stat().st_mode
+    tmp_path.chmod(stat.S_IRUSR | stat.S_IXUSR)
+    try:
+        if os.access(".", os.W_OK):
+            pytest.skip("Current user can write to read-only directories")
+        assert os.path.isdir(".")
+        waiter = BlockingLockFile(path_type("resource"))
+        with mock.patch.object(time, "sleep", side_effect=AssertionError("Must not retry")) as sleep:
+            with pytest.raises(OSError) as exc_info:
+                waiter._obtain_lock()
+            sleep.assert_not_called()
+        assert isinstance(exc_info.value.__cause__, PermissionError)
+        assert not waiter._has_lock()
+    finally:
+        tmp_path.chmod(original_mode)
+
+
+@pytest.mark.skipif(os.name != "posix", reason="Removing the current directory requires POSIX")
+@pytest.mark.parametrize("path_type", [str, pathlib.Path])
+def test_blocking_relative_lock_rejects_removed_cwd(tmp_path, monkeypatch, path_type):
+    monkeypatch.chdir(tmp_path)
+    tmp_path.rmdir()
+    waiter = BlockingLockFile(path_type("resource"))
+    with mock.patch.object(time, "sleep", side_effect=AssertionError("Must not retry")) as sleep:
+        with pytest.raises(OSError) as exc_info:
+            waiter._obtain_lock()
+        sleep.assert_not_called()
+    assert isinstance(exc_info.value.__cause__, FileNotFoundError)
+    assert not waiter._has_lock()