diff --git a/presubmit_canned_checks.py b/presubmit_canned_checks.py
index edd6332..620661f 100644
--- a/presubmit_canned_checks.py
+++ b/presubmit_canned_checks.py
@@ -771,29 +771,30 @@
   env['PYTHONPATH'] = input_api.os_path.pathsep.join(
       extra_paths_list + sys.path).encode('utf8')
 
-  def GetPylintCmd(files, extra, parallel):
+  def GetPylintCmd(flist, extra, parallel):
     # Windows needs help running python files so we explicitly specify
     # the interpreter to use. It also has limitations on the size of
     # the command-line, so we pass arguments via a pipe.
     cmd = [input_api.python_executable,
            input_api.os_path.join(_HERE, 'third_party', 'pylint.py'),
            '--args-on-stdin']
-    if len(files) == 1:
-      description = files[0]
+    if len(flist) == 1:
+      description = flist[0]
     else:
-      description = '%s files' % len(files)
+      description = '%s files' % len(flist)
 
+    args = extra_args[:]
     if extra:
-      cmd.extend(extra)
+      args.extend(extra)
       description += ' using %s' % (extra,)
     if parallel:
-      cmd.append('--jobs=%s' % input_api.cpu_count)
+      args.append('--jobs=%s' % input_api.cpu_count)
       description += ' on %d cores' % input_api.cpu_count
 
     return input_api.Command(
         name='Pylint (%s)' % description,
         cmd=cmd,
-        kwargs={'env': env, 'stdin': '\n'.join(files + extra_args)},
+        kwargs={'env': env, 'stdin': '\n'.join(args + flist)},
         message=error_type)
 
   # Always run pylint and pass it all the py files at once.
@@ -807,12 +808,18 @@
   if True:
     # pylint's cycle detection doesn't work in parallel, so spawn a second,
     # single-threaded job for just that check.
-    return [
-      GetPylintCmd(files, ["--disable=cyclic-import"], True),
-      GetPylintCmd(files, ["--disable=all", "--enable=cyclic-import"], False)
-    ]
+
+    # Some PRESUBMITs explicitly mention cycle detection.
+    if not any('R0401' in a or 'cyclic-import' in a for a in extra_args):
+      return [
+        GetPylintCmd(files, ["--disable=cyclic-import"], True),
+        GetPylintCmd(files, ["--disable=all", "--enable=cyclic-import"], False)
+      ]
+    else:
+      return [ GetPylintCmd(files, [], True) ]
+
   else:
-    return map(lambda x: GetPylintCmd([x], extra_args, 1), files)
+    return map(lambda x: GetPylintCmd([x], [], 1), files)
 
 
 def RunPylint(input_api, *args, **kwargs):
diff --git a/presubmit_support.py b/presubmit_support.py
index 4baee77..523bb79 100755
--- a/presubmit_support.py
+++ b/presubmit_support.py
@@ -313,6 +313,12 @@
 
     self.cpu_count = multiprocessing.cpu_count()
 
+    # this is done here because in RunTests, the current working directory has
+    # changed, which causes Pool() to explode fantastically when run on windows
+    # (because it tries to load the __main__ module, which imports lots of
+    # things relative to the current working directory).
+    self._run_tests_pool = multiprocessing.Pool(self.cpu_count)
+
     # The local path of the currently-being-processed presubmit script.
     self._current_presubmit_path = os.path.dirname(presubmit_path)
 
@@ -492,11 +498,8 @@
         if self.verbose:
           t.info = _PresubmitNotifyResult
     if len(tests) > 1 and parallel:
-      pool = multiprocessing.Pool()
       # async recipe works around multiprocessing bug handling Ctrl-C
-      msgs.extend(pool.map_async(CallCommand, tests).get(99999))
-      pool.close()
-      pool.join()
+      msgs.extend(self._run_tests_pool.map_async(CallCommand, tests).get(99999))
     else:
       msgs.extend(map(CallCommand, tests))
     return [m for m in msgs if m]
diff --git a/tests/presubmit_unittest.py b/tests/presubmit_unittest.py
index 3bec773..87832d4 100755
--- a/tests/presubmit_unittest.py
+++ b/tests/presubmit_unittest.py
@@ -2529,13 +2529,15 @@
     pylintrc = os.path.join(_ROOT, 'pylintrc')
 
     CommHelper(input_api,
-        ['pyyyyython', pylint, '--args-on-stdin', '--disable=cyclic-import',
-         '--jobs=2'],
-        env=mox.IgnoreArg(), stdin='file1.py\n--rcfile=%s' % pylintrc)
+        ['pyyyyython', pylint, '--args-on-stdin'],
+        env=mox.IgnoreArg(), stdin=
+               '--rcfile=%s\n--disable=cyclic-import\n--jobs=2\nfile1.py'
+               % pylintrc)
     CommHelper(input_api,
-        ['pyyyyython', pylint, '--args-on-stdin', '--disable=all',
-         '--enable=cyclic-import'],
-        env=mox.IgnoreArg(), stdin='file1.py\n--rcfile=%s' % pylintrc)
+        ['pyyyyython', pylint, '--args-on-stdin'],
+        env=mox.IgnoreArg(), stdin=
+               '--rcfile=%s\n--disable=all\n--enable=cyclic-import\nfile1.py'
+               % pylintrc)
     self.mox.ReplayAll()
 
     results = presubmit_canned_checks.RunPylint(
diff --git a/third_party/pylint/README.chromium b/third_party/pylint/README.chromium
index 2c3ecd9..3e468c2 100644
--- a/third_party/pylint/README.chromium
+++ b/third_party/pylint/README.chromium
@@ -8,3 +8,46 @@
 
 Local Modifications:
 - applied upstream fix https://bitbucket.org/logilab/pylint/commits/5df347467ee0
+- applied fix to work around bad interaction between sys.path manipulation in
+  pylint itself and multiprocessing's implementation on Windows (DIFF1)
+
+
+Diffs:
+DIFF1
+diff --git a/third_party/pylint/lint.py b/third_party/pylint/lint.py
+index e10ae56..082d8b3 100644
+--- a/third_party/pylint/lint.py
++++ b/third_party/pylint/lint.py
+@@ -671,7 +671,8 @@ class PyLinter(configuration.OptionsManagerMixIn,
+             files_or_modules = (files_or_modules,)
+
+         if self.config.jobs == 1:
+-            self._do_check(files_or_modules)
++            with fix_import_path(files_or_modules):
++                self._do_check(files_or_modules)
+         else:
+             # Hack that permits running pylint, on Windows, with -m switch
+             # and with --jobs, as in 'python -2 -m pylint .. --jobs'.
+@@ -1252,8 +1253,8 @@ group are mutually exclusive.'),
+
+         # insert current working directory to the python path to have a correct
+         # behaviour
+-        with fix_import_path(args):
+-            if self.linter.config.profile:
++        if self.linter.config.profile:
++            with fix_import_path(args):
+                 print('** profiled run', file=sys.stderr)
+                 import cProfile, pstats
+                 cProfile.runctx('linter.check(%r)' % args, globals(), locals(),
+@@ -1262,9 +1263,9 @@ group are mutually exclusive.'),
+                 data.strip_dirs()
+                 data.sort_stats('time', 'calls')
+                 data.print_stats(30)
+-            else:
+-                linter.check(args)
+-            linter.generate_reports()
++        else:
++            linter.check(args)
++        linter.generate_reports()
+         if exit:
+             sys.exit(self.linter.msg_status)
diff --git a/third_party/pylint/lint.py b/third_party/pylint/lint.py
index e10ae56..082d8b3 100644
--- a/third_party/pylint/lint.py
+++ b/third_party/pylint/lint.py
@@ -671,7 +671,8 @@
             files_or_modules = (files_or_modules,)
 
         if self.config.jobs == 1:
-            self._do_check(files_or_modules)
+            with fix_import_path(files_or_modules):
+                self._do_check(files_or_modules)
         else:
             # Hack that permits running pylint, on Windows, with -m switch
             # and with --jobs, as in 'python -2 -m pylint .. --jobs'.
@@ -1252,8 +1253,8 @@
 
         # insert current working directory to the python path to have a correct
         # behaviour
-        with fix_import_path(args):
-            if self.linter.config.profile:
+        if self.linter.config.profile:
+            with fix_import_path(args):
                 print('** profiled run', file=sys.stderr)
                 import cProfile, pstats
                 cProfile.runctx('linter.check(%r)' % args, globals(), locals(),
@@ -1262,9 +1263,9 @@
                 data.strip_dirs()
                 data.sort_stats('time', 'calls')
                 data.print_stats(30)
-            else:
-                linter.check(args)
-            linter.generate_reports()
+        else:
+            linter.check(args)
+        linter.generate_reports()
         if exit:
             sys.exit(self.linter.msg_status)