python / python/cpython

Segfault in `_Unpickler_MemoPut` (`_pickle.c`) from `Unpickler.memo` assignment with free-threading

Đang mở
#150,505 5 bình luận 0 reaction 0 người được giao Xem trên GitHub

Chưa có ai nhận issue này.

interpreter-core topic-free-threading type-bug
Ngôn ngữ chính
Python
Star
77.2k
Fork
35.9k
Chỉ số pull request đang chờ

Mô tả

Bug report

Bug description:

Unpickler_set_memo modifies self->memo and self->memo_size without any critical section.

When two threads set .memo on the same Unpickler instance concurrently, one can set self->memo = NULL while another is still indexing into it via _Unpickler_MemoPut, leading to a NULL-pointer dereference.

Reproducer:

import io
import pickle
from threading import Thread

shared_unpickler = pickle.Unpickler(io.BytesIO(b''))

def assign():
    for _ in range(10000):
        shared_unpickler.memo = {j: j for j in range(100)}

if __name__ == "__main__":
    threads = [Thread(target=assign) for _ in range(8)]
    for t in threads: t.start()
    for t in threads: t.join()

TSAN report:

WARNING: ThreadSanitizer: data race (pid=214122)
  Read of size 8 at 0x7dca529b9130 by thread T2:
    #0 _Unpickler_MemoPut /home/cpython/./Modules/_pickle.c:1631:22 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x2122f) 
    #1 Unpickler_set_memo /home/cpython/./Modules/_pickle.c:7804:17 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x26b77) 
    #2 getset_set /home/cpython/Objects/descrobject.c:250:16 (python3.16t+0x22d8fb) 
    #3 _PyObject_GenericSetAttrWithDict /home/cpython/Objects/object.c:2049:19 (python3.16t+0x2d844b) 
    #4 PyObject_GenericSetAttr /home/cpython/Objects/object.c:2120:12 (python3.16t+0x2d8d4b) 
    #5 Unpickler_setattr /home/cpython/./Modules/_pickle.c:7857:12 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x24eca) 
    #6 PyObject_SetAttr /home/cpython/Objects/object.c:1533:15 (python3.16t+0x2d480f) 
    #7 _PyEval_EvalFrameDefault /home/cpython/Python/generated_cases.c.h:11536:27 (python3.16t+0x45231a) 
    #8 _PyEval_EvalFrame /home/cpython/./Include/internal/pycore_ceval.h:122:16 (python3.16t+0x436463) 
    #9 _PyEval_Vector /home/cpython/Python/ceval.c:2134:12 (python3.16t+0x436463)
    #10 _PyFunction_Vectorcall /home/cpython/Objects/call.c (python3.16t+0x215013) 
    #11 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x216b11) 
    #12 _PyObject_VectorcallPrepend /home/cpython/Objects/call.c:855:20 (python3.16t+0x216b11)
    #13 method_vectorcall /home/cpython/Objects/classobject.c:55:12 (python3.16t+0x21a132) 
    #14 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x48ec15) 
    #15 context_run /home/cpython/Python/context.c:728:29 (python3.16t+0x48ec15)
    #16 method_vectorcall_FASTCALL_KEYWORDS /home/cpython/Objects/descrobject.c:421:24 (python3.16t+0x22e84c) 
    #17 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x2149a8) 
    #18 PyObject_Vectorcall /home/cpython/Objects/call.c:327:12 (python3.16t+0x2149a8)
    #19 _Py_VectorCallInstrumentation_StackRefSteal /home/cpython/Python/ceval.c:766:11 (python3.16t+0x4370c8) 
    #20 _PyEval_EvalFrameDefault /home/cpython/Python/generated_cases.c.h:1846:35 (python3.16t+0x43d022) 
    #21 _PyEval_EvalFrame /home/cpython/./Include/internal/pycore_ceval.h:122:16 (python3.16t+0x436463) 
    #22 _PyEval_Vector /home/cpython/Python/ceval.c:2134:12 (python3.16t+0x436463)
    #23 _PyFunction_Vectorcall /home/cpython/Objects/call.c (python3.16t+0x215013) 
    #24 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x216b11) 
    #25 _PyObject_VectorcallPrepend /home/cpython/Objects/call.c:855:20 (python3.16t+0x216b11)
    #26 method_vectorcall /home/cpython/Objects/classobject.c:55:12 (python3.16t+0x21a132) 
    #27 _PyVectorcall_Call /home/cpython/Objects/call.c:273:16 (python3.16t+0x214ca2) 
    #28 _PyObject_Call /home/cpython/Objects/call.c:348:16 (python3.16t+0x214ca2)
    #29 PyObject_Call /home/cpython/Objects/call.c:373:12 (python3.16t+0x214d07) 
    #30 thread_run /home/cpython/./Modules/_threadmodule.c:388:21 (python3.16t+0x61a708) 
    #31 pythread_wrapper /home/cpython/Python/thread_pthread.h:234:5 (python3.16t+0x5473bb) 

  Previous write of size 8 at 0x7dca529b9130 by thread T1:
    #0 Unpickler_set_memo /home/cpython/./Modules/_pickle.c:7816:21 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x26cc4) 
    #1 getset_set /home/cpython/Objects/descrobject.c:250:16 (python3.16t+0x22d8fb) 
    #2 _PyObject_GenericSetAttrWithDict /home/cpython/Objects/object.c:2049:19 (python3.16t+0x2d844b) 
    #3 PyObject_GenericSetAttr /home/cpython/Objects/object.c:2120:12 (python3.16t+0x2d8d4b) 
    #4 Unpickler_setattr /home/cpython/./Modules/_pickle.c:7857:12 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x24eca) 
    #5 PyObject_SetAttr /home/cpython/Objects/object.c:1533:15 (python3.16t+0x2d480f) 
    #6 _PyEval_EvalFrameDefault /home/cpython/Python/generated_cases.c.h:11536:27 (python3.16t+0x45231a) 
    #7 _PyEval_EvalFrame /home/cpython/./Include/internal/pycore_ceval.h:122:16 (python3.16t+0x436463) 
    #8 _PyEval_Vector /home/cpython/Python/ceval.c:2134:12 (python3.16t+0x436463)
    #9 _PyFunction_Vectorcall /home/cpython/Objects/call.c (python3.16t+0x215013) 
    #10 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x216b11) 
    #11 _PyObject_VectorcallPrepend /home/cpython/Objects/call.c:855:20 (python3.16t+0x216b11)
    #12 method_vectorcall /home/cpython/Objects/classobject.c:55:12 (python3.16t+0x21a132) 
    #13 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x48ec15) 
    #14 context_run /home/cpython/Python/context.c:728:29 (python3.16t+0x48ec15)
    #15 method_vectorcall_FASTCALL_KEYWORDS /home/cpython/Objects/descrobject.c:421:24 (python3.16t+0x22e84c) 
    #16 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x2149a8) 
    #17 PyObject_Vectorcall /home/cpython/Objects/call.c:327:12 (python3.16t+0x2149a8)
    #18 _Py_VectorCallInstrumentation_StackRefSteal /home/cpython/Python/ceval.c:766:11 (python3.16t+0x4370c8) 
    #19 _PyEval_EvalFrameDefault /home/cpython/Python/generated_cases.c.h:1846:35 (python3.16t+0x43d022) 
    #20 _PyEval_EvalFrame /home/cpython/./Include/internal/pycore_ceval.h:122:16 (python3.16t+0x436463) 
    #21 _PyEval_Vector /home/cpython/Python/ceval.c:2134:12 (python3.16t+0x436463)
    #22 _PyFunction_Vectorcall /home/cpython/Objects/call.c (python3.16t+0x215013) 
    #23 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x216b11) 
    #24 _PyObject_VectorcallPrepend /home/cpython/Objects/call.c:855:20 (python3.16t+0x216b11)
    #25 method_vectorcall /home/cpython/Objects/classobject.c:55:12 (python3.16t+0x21a132) 
    #26 _PyVectorcall_Call /home/cpython/Objects/call.c:273:16 (python3.16t+0x214ca2) 
    #27 _PyObject_Call /home/cpython/Objects/call.c:348:16 (python3.16t+0x214ca2)
    #28 PyObject_Call /home/cpython/Objects/call.c:373:12 (python3.16t+0x214d07) 
    #29 thread_run /home/cpython/./Modules/_threadmodule.c:388:21 (python3.16t+0x61a708) 
    #30 pythread_wrapper /home/cpython/Python/thread_pthread.h:234:5 (python3.16t+0x5473bb) 

SUMMARY: ThreadSanitizer: data race /home/cpython/./Modules/_pickle.c:1631:22 in _Unpickler_MemoPut
==================

==214455==ERROR: ThreadSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7afb5f96f25a bp 0x7afb187fd6f0 sp 0x7afb187fd690 T214460)
==214455==The signal is caused by a READ memory access.
==214455==Hint: address points to the zero page.
    #0 _Unpickler_MemoPut /home/cpython/./Modules/_pickle.c:1657:16 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x2125a) 
    #1 Unpickler_set_memo /home/cpython/./Modules/_pickle.c:7804:17 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x26b77) 
    #2 getset_set /home/cpython/Objects/descrobject.c:250:16 (python3.16t+0x22d8fb) 
    #3 _PyObject_GenericSetAttrWithDict /home/cpython/Objects/object.c:2049:19 (python3.16t+0x2d844b) 
    #4 PyObject_GenericSetAttr /home/cpython/Objects/object.c:2120:12 (python3.16t+0x2d8d4b) 
    #5 Unpickler_setattr /home/cpython/./Modules/_pickle.c:7857:12 (_pickle.cpython-316t-x86_64-linux-gnu.so+0x24eca) 
    #6 PyObject_SetAttr /home/cpython/Objects/object.c:1533:15 (python3.16t+0x2d480f) 
    #7 _PyEval_EvalFrameDefault /home/cpython/Python/generated_cases.c.h:11536:27 (python3.16t+0x45231a) 
    #8 _PyEval_EvalFrame /home/cpython/./Include/internal/pycore_ceval.h:122:16 (python3.16t+0x436463) 
    #9 _PyEval_Vector /home/cpython/Python/ceval.c:2134:12 (python3.16t+0x436463)
    #10 _PyFunction_Vectorcall /home/cpython/Objects/call.c (python3.16t+0x215013) 
    #11 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x216b11) 
    #12 _PyObject_VectorcallPrepend /home/cpython/Objects/call.c:855:20 (python3.16t+0x216b11)
    #13 method_vectorcall /home/cpython/Objects/classobject.c:55:12 (python3.16t+0x21a132) 
    #14 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x48ec15) 
    #15 context_run /home/cpython/Python/context.c:728:29 (python3.16t+0x48ec15)
    #16 method_vectorcall_FASTCALL_KEYWORDS /home/cpython/Objects/descrobject.c:421:24 (python3.16t+0x22e84c) 
    #17 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x2149a8) 
    #18 PyObject_Vectorcall /home/cpython/Objects/call.c:327:12 (python3.16t+0x2149a8)
    #19 _Py_VectorCallInstrumentation_StackRefSteal /home/cpython/Python/ceval.c:766:11 (python3.16t+0x4370c8) 
    #20 _PyEval_EvalFrameDefault /home/cpython/Python/generated_cases.c.h:1846:35 (python3.16t+0x43d022) 
    #21 _PyEval_EvalFrame /home/cpython/./Include/internal/pycore_ceval.h:122:16 (python3.16t+0x436463) 
    #22 _PyEval_Vector /home/cpython/Python/ceval.c:2134:12 (python3.16t+0x436463)
    #23 _PyFunction_Vectorcall /home/cpython/Objects/call.c (python3.16t+0x215013) 
    #24 _PyObject_VectorcallTstate /home/cpython/./Include/internal/pycore_call.h:144:11 (python3.16t+0x216b11) 
    #25 _PyObject_VectorcallPrepend /home/cpython/Objects/call.c:855:20 (python3.16t+0x216b11)
    #26 method_vectorcall /home/cpython/Objects/classobject.c:55:12 (python3.16t+0x21a132) 
    #27 _PyVectorcall_Call /home/cpython/Objects/call.c:273:16 (python3.16t+0x214ca2) 
    #28 _PyObject_Call /home/cpython/Objects/call.c:348:16 (python3.16t+0x214ca2)
    #29 PyObject_Call /home/cpython/Objects/call.c:373:12 (python3.16t+0x214d07) 
    #30 thread_run /home/cpython/./Modules/_threadmodule.c:388:21 (python3.16t+0x61a708) 
    #31 pythread_wrapper /home/cpython/Python/thread_pthread.h:234:5 (python3.16t+0x5473bb) 
    #32 __tsan_thread_start_func <null> (python3.16t+0xf9182) 
    #33 start_thread nptl/pthread_create.c:447:8 (libc.so.6+0x9caa3) (BuildId: 8e9fd827446c24067541ac5390e6f527fb5947bb)
    #34 clone3 misc/../sysdeps/unix/sysv/linux/x86_64/clone3.S:78 (libc.so.6+0x129c6b) (BuildId: 8e9fd827446c24067541ac5390e6f527fb5947bb)

ThreadSanitizer can not provide additional info.
SUMMARY: ThreadSanitizer: SEGV /home/cpython/./Modules/_pickle.c:1657:16 in _Unpickler_MemoPut
==214455==ABORTING
CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs
  • gh-150550

Hướng dẫn đóng góp

Mở hướng dẫn đóng góp

Bắt đầu từ đâu

  1. Đọc hết issue, rồi đọc hướng dẫn đóng góp của dự án.
  2. Bình luận trên issue rằng bạn sẽ nhận — tránh hai người làm cùng một việc.
  3. Fork repository và làm thay đổi trên một nhánh.
  4. Mở pull request có tham chiếu số hiệu của issue.

Hướng nghiên cứu

Bắt đầu trong Modules/_pickle.c tại _Unpickler_MemoPut và Unpickler_set_memo, sử dụng threaded reproducer được cung cấp và báo cáo TSAN để truy vết race. Xem lại PR được liên kết gh-150550 và xác minh rằng các phép gán đồng thời cho Unpickler.memo không còn gây ra data race hoặc dereference con trỏ NULL.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.

Đánh giá

Công nghệ
c, python
Lĩnh vực
backend
Loại issue
Lỗi
Độ khó
4/5
Thời gian dự kiến
3-5 ngày
Mức độ hoạt động
Đình trệ
Độ rõ ràng
Khá rõ ràng
Mức phù hợp với người mới
25/100

Nhận issue mới trong hộp thư của bạn

Bản tóm tắt ngắn những issue GitHub phù hợp với người mới.