Bus error in Python with C extension

Question

Recently i have been working on programming python module with C extension. ( python2.7, gcc 4.1.2) Once done and testing. i found following bus error.

does anybody know why?

p.s before i got this error. i fixed 'return Py_False related error' described in

Application gives segmentation fault randomly in python extension functions in c++

Core was generated by python2.7 app.py --debug=False --multi_slaves=True

Program terminated with signal 7, Bus error.
#0 0x0000003d22272cf1 in _int_malloc () from /lib64/libc.so.6
(gdb) where
#0 0x0000003d22272cf1 in _int_malloc () from /lib64/libc.so.6
#1 0x0000003d22274e4e in malloc () from /lib64/libc.so.6
#2 0x00000000004d3069 in _PyObject_GC_Malloc (basicsize=<value optimized out>) at Modules/gcmodule.c:1445
#3 0x000000000046408c in PyType_GenericAlloc (type=0x768360, nitems=0) at Objects/typeobject.c:753
#4 0x00000000004477ec in dict_new (type=0x3d225539e0, args=, kwds=0x7fff8dcb4eb0) at Objects/dictobject.c:2301
#5 0x00000000004661c3 in type_call (type=0x3d225539e0, args=0x2b3e5a521050, kwds=0x2239bca0) at Objects/typeobject.c:721
#6 0x00000000004189cd in PyObject_Call (func=0x768360, arg=0x2b3e5a521050, kw=0x2239bca0) at Objects/abstract.c:2529

c extension code looks like this

static PyObject* analyze( PyObject *self, PyObject *args )
{
    int     ret;
    char*   in;

    // global variables : void* obj, char* outbuf, int outbuf_size;
    if (PyArg_ParseTuple(args, "s", &in)){
        ret = process(obj, in, outbuf, outbuf_size);
        if ( ret == SUCCESS ) {
            PyObject* py_out = PyString_FromString(outbuf);
            return py_out;
        } else {
            Py_INCREF(Py_False);
            return Py_False;
        }
    } else {
        Py_INCREF(Py_False);
        return Py_False;
    }
}

~

That very much looks like your module messes something up. Can you post the complete source code of a module that exhibits the problem? — phihag
– phihag, Commented Apr 17, 2013 at 7:41
c extension module, first initialize void* obj, and then call analyze(obj, in, ...). problem appears here. — dsindex
– dsindex, Commented Apr 17, 2013 at 9:10
Although the problem appears in analyze, the actual error is most likely somewhere completely different (say, a double free). Can you post complete code that still exhibits the problem? Also, the example code is obviously invalid - outbuf is never declared. — phihag
– phihag, Commented Apr 17, 2013 at 9:14
I would think the usual thing to do would be to compile with --debug=True and run your code through a debugger; that should at least give you the exact point where things crash. — user707650
– user707650, Commented Apr 17, 2013 at 9:18
@phihag outbuf is global variable. and process() is very long c code. so it's not proper to post here. sorry ^^;; — dsindex
– dsindex, Commented Apr 17, 2013 at 9:26

jamshid · Accepted Answer · 2019-01-21 05:39:49Z

0

FWIW I was getting a Bus error from a python program. Turned out to be related to it allocating shared memory. I was running it in a docker container and had to set docker run ... --shm_size=1g as described in: https://goblincoding.com/2018/02/19/docker-bus-error-no-space-left-on-device/

answered Jan 21, 2019 at 5:39

jamshid

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