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Bug description:
I built cpython (3.13 branch) with free-threading and TSAN. The following python code reports TSAN warnings:
import ctypes
import concurrent.futures
import threading
def raw_func(x):
pass
def test_ctypes():
def lookup():
prototype = ctypes.CFUNCTYPE(None, ctypes.c_void_p)
return prototype(raw_func)
ctypes_args = ()
func = lookup()
packed_args = (ctypes.c_void_p * len(ctypes_args))()
for argNum in range(len(ctypes_args)):
packed_args[argNum] = ctypes.cast(ctypes_args[argNum], ctypes.c_void_p)
func(packed_args)
if __name__ == "__main__":
num_workers = 20
barrier = threading.Barrier(num_workers)
def closure():
barrier.wait()
test_ctypes()
with concurrent.futures.ThreadPoolExecutor(max_workers=num_workers) as executor:
futures = []
for i in range(num_workers):
futures.append(executor.submit(closure))
assert len(list(f.result() for f in futures)) == num_workersTSAN report extract:
WARNING: ThreadSanitizer: data race (pid=261974)
Write of size 4 at 0x7fffbe0d0430 by thread T5:
#0 generic_pycdata_new /project/cpython/./Modules/_ctypes/_ctypes.c:3387:17 (_ctypes.cpython-313t-x86_64-linux-gnu.so+0xdbb7) (BuildId: 6a7727f376cee83a3124898fe6eb84e45e3a54bc)
#1 PyCFuncPtr_new /project/cpython/./Modules/_ctypes/_ctypes.c:3963:32 (_ctypes.cpython-313t-x86_64-linux-gnu.so+0x18bbb) (BuildId: 6a7727f376cee83a3124898fe6eb84e45e3a54bc)
#2 type_call /project/cpython/Objects/typeobject.c:1981:11 (python3.13t+0x2eb032) (BuildId: 65e52348ca9319985f9f5e265fd43aab2c867d59)
#3 _PyObject_MakeTpCall /project/cpython/Objects/call.c:242:18 (python3.13t+0x1ea44c) (BuildId: 65e52348ca9319985f9f5e265fd43aab2c867d59)
#4 _PyObject_VectorcallTstate /project/cpython/./Include/internal/pycore_call.h:166:16 (python3.13t+0x1eb0a8) (BuildId: 65e52348ca9319985f9f5e265fd43aab2c867d59)
#5 PyObject_Vectorcall /project/cpython/Objects/call.c:327:12 (python3.13t+0x1eb0a8)
Related #128182
CPython versions tested on:
3.13
Operating systems tested on:
Linux
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bugs and security fixesbugs and security fixesbugs and security fixesbugs and security fixesC modules in the Modules dirC modules in the Modules dirAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error