[cx-oracle-users] Segmentation fault in Python 3 - Cursor - chained exceptions

[Boris D. <bor...@gm...>]

Hi all,

The following test program gives a segmentation fault:

C:\>python
Python 3.3.3 (v3.3.3:c3896275c0f6, Nov 18 2013, 21:19:30) [MSC v.1600 64
bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> import cx_Oracle
>>> c=cx_Oracle.connect(<connect string>).cursor()
>>> try:
...     c.execute("select")
... except:
...     try:
...             c.execute("select")
...     except:
...             pass
...

C:\>

Access Violation
Faulting application name: python.exe
Fault offset: 0x000000000000cacd


Platform: 64bit, Win7, Oracle Client 11g (11.2.0.1.0), python 3.3.3,
cx_Oracle 5.1.2



At a guess, the problem is because in the function Cursor_SetErrorOffset()
/Cursor.c/:

static void Cursor_SetErrorOffset(
    udt_Cursor *self)                   // cursor to get the error offset
from
{
    PyObject *type, *value, *traceback;
    udt_Error *error;

    PyErr_Fetch(&type, &value, &traceback);
    if (type == g_DatabaseErrorException) {
        error = (udt_Error*) value;
        OCIAttrGet(self->handle, OCI_HTYPE_STMT, &error->offset, 0,
                OCI_ATTR_PARSE_ERROR_OFFSET,
self->environment->errorHandle);
    }
    PyErr_Restore(type, value, traceback);
}

OCIAttrGet() call attempts to write a value to the address
/&error->offset/,
therefore after the end of an allocated memory block of the borrowed
pointer /PyObject *value/

typedef struct {
    PyObject_HEAD
    sb4 code;
    ub4 offset;
    PyObject *message;
    const char *context;
} udt_Error;


Commenting it out /* OCIAttrGet(self->handle, OCI_HTYPE_STMT,
&error->offset, 0, OCI_ATTR_PARSE_ERROR_OFFSET,
self->environment->errorHandle);*/
fix this crash!


Regards,
Boris