c++ - 应用程序在 c++ 中的 python 扩展函数中随机给出分段错误

Question

我在 c++ 中的 python 扩展中遇到了一些奇怪的问题。我感谢任何帮助或建议。

设置上下文。

我在 C++ 中使用嵌入式 python 来执行 python 脚本。我还在 c++ 中使用 python 扩展来赋予 python 脚本调用 C++ 函数的能力。

什么是问题？

当我从模块“方法表”中评论方法条目时，如下所示。应用程序永远不会崩溃，或者我根本没有遇到段错误。

static PyMethodDef sa_methods[] = {

//{"GetBlue",(PyCFunction)sa_GetBlue,METH_VARARGS,PyDoc_STR("fetches Blue color")},

//{"GetRed",(PyCFunction)sa_GetRed,METH_VARARGS,PyDoc_STR("fetches Red color")},

{"GetYellow",(PyCFunction)sa_GetYellow,METH_VARARGS,PyDoc_STR("fetches yellow color")},                        

{"GetPink",(PyCFunction)sa_GetPink,METH_VARARGS,PyDoc_STR("fetches pink color")},

{NULL, NULL, 0, NULL}

};

当我从模块“方法表”的方法条目中删除方法注释时，如下所示。应用程序总是在随机处理 20000 到 50000 个请求之间崩溃。

static PyMethodDef sa_methods[] = {

{"GetBlue",(PyCFunction)sa_GetBlue,METH_VARARGS,PyDoc_STR("fetches Blue color")},

{"GetRed",(PyCFunction)sa_GetRed,METH_VARARGS,PyDoc_STR("fetches Red color")},

{"GetYellow",(PyCFunction)sa_GetYellow,METH_VARARGS,PyDoc_STR("fetches yellow color")},                        

{"GetPink",(PyCFunction)sa_GetPink,METH_VARARGS,PyDoc_STR("fetches pink color")},

{NULL, NULL, 0, NULL}

};

我将以上两个方法保留为空，它们只是返回 Py_False。

请在我每次得到的堆栈跟踪下方找到。

#0  0x00002b700146c4d7 in PyNumber_CoerceEx (pv=0x41801798, pw=0x41801790) at Objects/object.c:1599
#1  0x00002b700142d6e3 in binary_op1 (v=0x2aaaac079600, w=0x2b7001750550, op_slot=16) at Objects/abstract.c:929
#2  0x00002b7001431e08 in PyNumber_Multiply (v=0x41801798, w=0x41801790) at Objects/abstract.c:1188
#3  0x00002b70014c4326 in PyEval_EvalFrameEx (f=0x8127780, throwflag=<value optimized out>) at Python/ceval.c:1118
#4  0x00002b70014c8493 in call_function (f=0x996e660, throwflag=<value optimized out>) at Python/ceval.c:3792
#5  PyEval_EvalFrameEx (f=0x996e660, throwflag=<value optimized out>) at Python/ceval.c:2389
#6  0x00002b70014c8493 in call_function (f=0x2aaac30aeb50, throwflag=<value optimized out>) at Python/ceval.c:3792
#7  PyEval_EvalFrameEx (f=0x2aaac30aeb50, throwflag=<value optimized out>) at Python/ceval.c:2389
#8  0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x2aaaad7dc558, globals=<value optimized out>, locals=<value optimized out>, args=0x2aaac6ab59a0, argcount=2,
    kws=0x2aaac6ab59b0, kwcount=0, defs=0x7819128, defcount=1, closure=0x0) at Python/ceval.c:2968
#9  0x00002b70014c6df3 in call_function (f=0x2aaac6ab57d0, throwflag=<value optimized out>) at Python/ceval.c:3802
#10 PyEval_EvalFrameEx (f=0x2aaac6ab57d0, throwflag=<value optimized out>) at Python/ceval.c:2389
#11 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x2aaabdf8e828, globals=<value optimized out>, locals=<value optimized out>, args=0x2aaac65bcbf0, argcount=2,
    kws=0x2aaac65bcc00, kwcount=0, defs=0x7819c28, defcount=1, closure=0x0) at Python/ceval.c:2968
#12 0x00002b70014c6df3 in call_function (f=0x2aaac65bca40, throwflag=<value optimized out>) at Python/ceval.c:3802
#13 PyEval_EvalFrameEx (f=0x2aaac65bca40, throwflag=<value optimized out>) at Python/ceval.c:2389
#14 0x00002b70014c8493 in call_function (f=0x2aaac6301630, throwflag=<value optimized out>) at Python/ceval.c:3792
#15 PyEval_EvalFrameEx (f=0x2aaac6301630, throwflag=<value optimized out>) at Python/ceval.c:2389
#16 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x6c7f558, globals=<value optimized out>, locals=<value optimized out>, args=0x2aaac55963e8, argcount=2,
    kws=0x2aaac55963f8, kwcount=0, defs=0xd83fce8, defcount=1, closure=0x0) at Python/ceval.c:2968
#17 0x00002b70014c6df3 in call_function (f=0x2aaac5596240, throwflag=<value optimized out>) at Python/ceval.c:3802
#18 PyEval_EvalFrameEx (f=0x2aaac5596240, throwflag=<value optimized out>) at Python/ceval.c:2389
#19 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x6c7fcd8, globals=<value optimized out>, locals=<value optimized out>, args=0x2aaac6fbc328, argcount=2,
    kws=0x2aaac6fbc338, kwcount=0, defs=0xd83fc68, defcount=1, closure=0x0) at Python/ceval.c:2968
#20 0x00002b70014c6df3 in call_function (f=0x2aaac6fbc1a0, throwflag=<value optimized out>) at Python/ceval.c:3802
#21 PyEval_EvalFrameEx (f=0x2aaac6fbc1a0, throwflag=<value optimized out>) at Python/ceval.c:2389
#22 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x6c7f648, globals=<value optimized out>, locals=<value optimized out>, args=0x1, argcount=0, kws=0x2aaac3e32558,
    kwcount=0, defs=0xd83ffa8, defcount=1, closure=0x0) at Python/ceval.c:2968
#23 0x00002b70014c6df3 in call_function (f=0x2aaac3e323d0, throwflag=<value optimized out>) at Python/ceval.c:3802
#24 PyEval_EvalFrameEx (f=0x2aaac3e323d0, throwflag=<value optimized out>) at Python/ceval.c:2389
#25 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x2aaaad7f70a8, globals=<value optimized out>, locals=<value optimized out>, args=0x0, argcount=0, kws=0x1325c6a8,
    kwcount=0, defs=0x0, defcount=0, closure=0x2aaaad18e990) at Python/ceval.c:2968
#26 0x00002b70014c6df3 in call_function (f=0x1325c480, throwflag=<value optimized out>) at Python/ceval.c:3802
#27 PyEval_EvalFrameEx (f=0x1325c480, throwflag=<value optimized out>) at Python/ceval.c:2389
#28 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x2aaaad7f77b0, globals=<value optimized out>, locals=<value optimized out>, args=0x1, argcount=1, kws=0x2aaac5ec1d08,
    kwcount=0, defs=0x2aaaacfdf5e8, defcount=1, closure=0x0) at Python/ceval.c:2968
#29 0x00002b70014c6df3 in call_function (f=0x2aaac5ec1b00, throwflag=<value optimized out>) at Python/ceval.c:3802
#30 PyEval_EvalFrameEx (f=0x2aaac5ec1b00, throwflag=<value optimized out>) at Python/ceval.c:2389
#31 0x00002b70014c8493 in call_function (f=0xa926080, throwflag=<value optimized out>) at Python/ceval.c:3792
#32 PyEval_EvalFrameEx (f=0xa926080, throwflag=<value optimized out>) at Python/ceval.c:2389
#33 0x00002b70014c8493 in call_function (f=0x8e4bd40, throwflag=<value optimized out>) at Python/ceval.c:3792
#34 PyEval_EvalFrameEx (f=0x8e4bd40, throwflag=<value optimized out>) at Python/ceval.c:2389
#35 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x2aaabc9f7648, globals=<value optimized out>, locals=<value optimized out>, args=0x9ff5f58, argcount=1,
---Type <return> to continue, or q <return> to quit---
    kws=0x9ff5f60, kwcount=0, defs=0x0, defcount=0, closure=0x2aaaacfdfc50) at Python/ceval.c:2968
#36 0x00002b70014c6df3 in call_function (f=0x9ff5dc0, throwflag=<value optimized out>) at Python/ceval.c:3802
#37 PyEval_EvalFrameEx (f=0x9ff5dc0, throwflag=<value optimized out>) at Python/ceval.c:2389
#38 0x00002b70014c8493 in call_function (f=0xdb993e0, throwflag=<value optimized out>) at Python/ceval.c:3792
#39 PyEval_EvalFrameEx (f=0xdb993e0, throwflag=<value optimized out>) at Python/ceval.c:2389
#40 0x00002b70014c8d9f in PyEval_EvalCodeEx (co=0x2aaabd820990, globals=<value optimized out>, locals=<value optimized out>, args=0x2aaaacfdf8a8, argcount=1, kws=0x0,
    kwcount=0, defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2968
#41 0x00002b700145815d in function_call (func=0x7d898c0, arg=0x2aaaacfdf890, kw=0x0) at Objects/funcobject.c:524
#42 0x00002b700142d318 in PyObject_Call (func=0x7d898c0, arg=0x2aaaacfdf890, kw=0x0) at Objects/abstract.c:2492
#43 0x00002b700143cd7f in instancemethod_call (func=<value optimized out>, arg=0x2aaaacfdf890, kw=0x0) at Objects/classobject.c:2579
#44 0x00002b700142d318 in PyObject_Call (func=0x7554690, arg=0x2aaaac04d050, kw=0x0) at Objects/abstract.c:2492
#45 0x00002b70014c0e16 in PyEval_CallObjectWithKeywords (func=0x7554690, arg=0x2aaaac04d050, kw=0x0) at Python/ceval.c:3575
#46 0x00002b70014f9dcd in t_bootstrap (boot_raw=0x2aaac76e67c0) at ./Modules/threadmodule.c:425
#47 0x00000033c720677d in start_thread () from /lib64/libpthread.so.0
#48 0x00000033c66d33ed in clone () from /lib64/libc.so.6

score 5 · Accepted Answer

我得到了解决这个问题的方法，这最终让我和我的客户都松了一口气。

这是原因和解决方案。

函数“sa_GetBlue”和“sa_GetRed”返回“Py_False”。在返回“Py_False”或“Py_True”之前，您需要增加保存这些值的变量的引用计数，否则可能会破坏解释器的内存状态；它不会立即崩溃，但可能随时崩溃。就我而言，它在处理 20000 到 50000 个请求后崩溃了。

请查看下面的链接以了解更多关于我要解释的内容。

为什么-does-python-keep-a-reference-count-on-false-and-true

@doomster 和 @Omnifarious；感谢您提供的评论和指导。

c++ - 应用程序在 c++ 中的 python 扩展函数中随机给出分段错误

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