[3.6] bpo-30604: Move co_extra_freefuncs to interpreter state to avoid crashes in threads (#2015)
* Move co_extra_freefuncs to interpreter state to avoid crashes in
multi-threaded scenarios involving deletion of code objects
* Don't require that extra be zero initialized
* Build test list instead of defining empty test class
* Ensure extra is always assigned on success
* Keep the old fields in the thread state object, just don't use them
Add new linked list of code extra objects on a per-interpreter basis
so that interpreter state size isn't changed
* Rename __PyCodeExtraState_Get and add comment about it going away in 3.7
Fix sort order of import's in test_code.py
* Remove an extraneous space
* Remove docstrings for comments
* Touch up formatting
* Fix casing of coextra local
* Fix casing of another variable
* Prefix PyCodeExtraState with __ to match C API for getting it
* Update NEWS file for bpo-30604
diff --git a/Lib/test/test_code.py b/Lib/test/test_code.py
index 7975ea0..9f9df9d 100644
--- a/Lib/test/test_code.py
+++ b/Lib/test/test_code.py
@@ -103,9 +103,11 @@
"""
import sys
+import threading
import unittest
import weakref
-from test.support import run_doctest, run_unittest, cpython_only
+from test.support import (run_doctest, run_unittest, cpython_only,
+ check_impl_detail)
def consts(t):
@@ -212,11 +214,106 @@
self.assertTrue(self.called)
+if check_impl_detail(cpython=True):
+ import ctypes
+ py = ctypes.pythonapi
+ freefunc = ctypes.CFUNCTYPE(None,ctypes.c_voidp)
+
+ RequestCodeExtraIndex = py._PyEval_RequestCodeExtraIndex
+ RequestCodeExtraIndex.argtypes = (freefunc,)
+ RequestCodeExtraIndex.restype = ctypes.c_ssize_t
+
+ SetExtra = py._PyCode_SetExtra
+ SetExtra.argtypes = (ctypes.py_object, ctypes.c_ssize_t, ctypes.c_voidp)
+ SetExtra.restype = ctypes.c_int
+
+ GetExtra = py._PyCode_GetExtra
+ GetExtra.argtypes = (ctypes.py_object, ctypes.c_ssize_t,
+ ctypes.POINTER(ctypes.c_voidp))
+ GetExtra.restype = ctypes.c_int
+
+ LAST_FREED = None
+ def myfree(ptr):
+ global LAST_FREED
+ LAST_FREED = ptr
+
+ FREE_FUNC = freefunc(myfree)
+ FREE_INDEX = RequestCodeExtraIndex(FREE_FUNC)
+
+ class CoExtra(unittest.TestCase):
+ def get_func(self):
+ # Defining a function causes the containing function to have a
+ # reference to the code object. We need the code objects to go
+ # away, so we eval a lambda.
+ return eval('lambda:42')
+
+ def test_get_non_code(self):
+ f = self.get_func()
+
+ self.assertRaises(SystemError, SetExtra, 42, FREE_INDEX,
+ ctypes.c_voidp(100))
+ self.assertRaises(SystemError, GetExtra, 42, FREE_INDEX,
+ ctypes.c_voidp(100))
+
+ def test_bad_index(self):
+ f = self.get_func()
+ self.assertRaises(SystemError, SetExtra, f.__code__,
+ FREE_INDEX+100, ctypes.c_voidp(100))
+ self.assertEqual(GetExtra(f.__code__, FREE_INDEX+100,
+ ctypes.c_voidp(100)), 0)
+
+ def test_free_called(self):
+ # Verify that the provided free function gets invoked
+ # when the code object is cleaned up.
+ f = self.get_func()
+
+ SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(100))
+ del f
+ self.assertEqual(LAST_FREED, 100)
+
+ def test_get_set(self):
+ # Test basic get/set round tripping.
+ f = self.get_func()
+
+ extra = ctypes.c_voidp()
+
+ SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(200))
+ # reset should free...
+ SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(300))
+ self.assertEqual(LAST_FREED, 200)
+
+ extra = ctypes.c_voidp()
+ GetExtra(f.__code__, FREE_INDEX, extra)
+ self.assertEqual(extra.value, 300)
+ del f
+
+ def test_free_different_thread(self):
+ # Freeing a code object on a different thread then
+ # where the co_extra was set should be safe.
+ f = self.get_func()
+ class ThreadTest(threading.Thread):
+ def __init__(self, f, test):
+ super().__init__()
+ self.f = f
+ self.test = test
+ def run(self):
+ del self.f
+ self.test.assertEqual(LAST_FREED, 500)
+
+ SetExtra(f.__code__, FREE_INDEX, ctypes.c_voidp(500))
+ tt = ThreadTest(f, self)
+ del f
+ tt.start()
+ tt.join()
+ self.assertEqual(LAST_FREED, 500)
+
def test_main(verbose=None):
from test import test_code
run_doctest(test_code, verbose)
- run_unittest(CodeTest, CodeConstsTest, CodeWeakRefTest)
-
+ tests = [CodeTest, CodeConstsTest, CodeWeakRefTest]
+ if check_impl_detail(cpython=True):
+ tests.append(CoExtra)
+ run_unittest(*tests)
if __name__ == "__main__":
test_main()