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TSan: data race with PyTypeObject version tag #116909
Description
Bug report
Bug description:
Running test_capi with TSan enabled and the GIL enabled yields the following race condition:
test_isolated_subinterpreter (test.test_capi.test_misc.TestPendingCalls.test_isolated_subinterpreter) ...
==================
WARNING: ThreadSanitizer: data race (pid=84714)
Read of size 4 at 0x55c8c4c10f90 by thread T1:
#0 assign_version_tag /home/antoine/cpython/default/Objects/typeobject.c:1012:13 (python+0x327919) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#1 _PyType_Lookup /home/antoine/cpython/default/Objects/typeobject.c:5087:23 (python+0x3290ab) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#2 _PyObject_GetMethod /home/antoine/cpython/default/Objects/object.c:1462:23 (python+0x2d9f67) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#3 _PyEval_EvalFrameDefault /home/antoine/cpython/default/Python/generated_cases.c.h:3561:25 (python+0x443799) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#4 _PyEval_EvalFrame /home/antoine/cpython/default/./Include/internal/pycore_ceval.h:114:16 (python+0x26cd12) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#5 gen_send_ex2 /home/antoine/cpython/default/Objects/genobject.c:228:24 (python+0x26cd12)
#6 gen_iternext /home/antoine/cpython/default/Objects/genobject.c:586:9 (python+0x26a0d2) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#7 builtin_next /home/antoine/cpython/default/Python/bltinmodule.c:1534:11 (python+0x4172a3) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
[...]
Previous write of size 4 at 0x55c8c4c10f90 by main thread:
#0 assign_version_tag /home/antoine/cpython/default/Objects/typeobject.c (python+0x32794d) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#1 _PyType_Lookup /home/antoine/cpython/default/Objects/typeobject.c:5087:23 (python+0x3290ab) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#2 _PyObject_GetMethod /home/antoine/cpython/default/Objects/object.c:1462:23 (python+0x2d9f67) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#3 _PyEval_EvalFrameDefault /home/antoine/cpython/default/Python/generated_cases.c.h:3561:25 (python+0x443799) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#4 _PyEval_EvalFrame /home/antoine/cpython/default/./Include/internal/pycore_ceval.h:114:16 (python+0x26cd12) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#5 gen_send_ex2 /home/antoine/cpython/default/Objects/genobject.c:228:24 (python+0x26cd12)
#6 gen_iternext /home/antoine/cpython/default/Objects/genobject.c:586:9 (python+0x26a0d2) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
#7 builtin_next /home/antoine/cpython/default/Python/bltinmodule.c:1534:11 (python+0x4172a3) (BuildId: 80a378e5bf8e9a3b503d1ddb455283576a308db6)
CPython versions tested on:
CPython main branch
Operating systems tested on:
Linux
Activity
pitrou commentedon Mar 16, 2024
@colesbury @ericsnowcurrently
pitrou commentedon Mar 16, 2024
From what I can see, the problem is accessing
_PyRuntime.types.next_version_tagwithout synchronization and without atomic instructions.pythongh-116909: fix data race with versions in typeobject
kumaraditya303 commentedon Jul 4, 2025
Fixed by #135794