cpython/Lib/test/test_free_threading/test_races.py

135 lines
3.5 KiB
Python

# It's most useful to run these tests with ThreadSanitizer enabled.
import sys
import functools
import threading
import time
import unittest
from test.support import threading_helper
class TestBase(unittest.TestCase):
pass
def do_race(func1, func2):
"""Run func1() and func2() repeatedly in separate threads."""
n = 1000
barrier = threading.Barrier(2)
def repeat(func):
barrier.wait()
for _i in range(n):
func()
threads = [
threading.Thread(target=functools.partial(repeat, func1)),
threading.Thread(target=functools.partial(repeat, func2)),
]
for thread in threads:
thread.start()
for thread in threads:
thread.join()
@threading_helper.requires_working_threading()
class TestRaces(TestBase):
def test_racing_cell_set(self):
"""Test cell object gettr/settr properties."""
def nested_func():
x = 0
def inner():
nonlocal x
x += 1
# This doesn't race because LOAD_DEREF and STORE_DEREF on the
# cell object use critical sections.
do_race(nested_func, nested_func)
def nested_func2():
x = 0
def inner():
y = x
frame = sys._getframe(1)
frame.f_locals["x"] = 2
return inner
def mutate_func2():
inner = nested_func2()
cell = inner.__closure__[0]
old_value = cell.cell_contents
cell.cell_contents = 1000
time.sleep(0)
cell.cell_contents = old_value
time.sleep(0)
# This revealed a race with cell_set_contents() since it was missing
# the critical section.
do_race(nested_func2, mutate_func2)
def test_racing_cell_cmp_repr(self):
"""Test cell object compare and repr methods."""
def nested_func():
x = 0
y = 0
def inner():
return x + y
return inner.__closure__
cell_a, cell_b = nested_func()
def mutate():
cell_a.cell_contents += 1
def access():
cell_a == cell_b
s = repr(cell_a)
# cell_richcompare() and cell_repr used to have data races
do_race(mutate, access)
def test_racing_load_super_attr(self):
"""Test (un)specialization of LOAD_SUPER_ATTR opcode."""
class C:
def __init__(self):
try:
super().__init__
super().__init__()
except RuntimeError:
pass # happens if __class__ is replaced with non-type
def access():
C()
def mutate():
# Swap out the super() global with a different one
real_super = super
globals()["super"] = lambda s=1: s
time.sleep(0)
globals()["super"] = real_super
time.sleep(0)
# Swap out the __class__ closure value with a non-type
cell = C.__init__.__closure__[0]
real_class = cell.cell_contents
cell.cell_contents = 99
time.sleep(0)
cell.cell_contents = real_class
# The initial PR adding specialized opcodes for LOAD_SUPER_ATTR
# had some races (one with the super() global changing and one
# with the cell binding being changed).
do_race(access, mutate)
if __name__ == "__main__":
unittest.main()