New submission from Charles-François Natali:
The following segfaults in _PyObject_GenericGetAttrWithDict:
"""
from socket import socketpair
from _multiprocessing import Connection
class Crash(Connection):
pass
_, w = socketpair()
Crash(w.fileno()).bar
"""
#0 _PyObject_GenericGetAttrWithDict (dict=0xa6b001c, name=0xb7281020,
obj=0x8c12478) at Objects/object.c:1427
#1 PyObject_GenericGetAttr (obj=0x8c12478, name=0xb7281020) at
Objects/object.c:1461
(gdb) p *(obj + obj->ob_type->tp_dictoffset)
$8 = {ob_refcnt = 0, ob_type = 0x0}
It's probably not specific to this example, but I'm not familiar enough with
object construction/descriptors to know what's going on here.
Note that the following atch fixes the crash, but I don't know why:
"""
--- a/Modules/_multiprocessing/connection.h Wed Apr 15 19:30:38 2015 +0100
+++ b/Modules/_multiprocessing/connection.h Wed Jun 10 20:25:15 2015 +0100
@@ -58,7 +58,7 @@
return NULL;
}
- self = PyObject_New(ConnectionObject, type);
+ self = type->tp_alloc(type, 0);
if (self == NULL)
return NULL;
@@ -86,7 +86,7 @@
CLOSE(self->handle);
Py_END_ALLOW_THREADS
}
- PyObject_Del(self);
+ Py_TYPE(self)->tp_free((PyObject*)self);
}
/*
"""
----------
messages: 245140
nosy: neologix, pitrou
priority: normal
severity: normal
stage: needs patch
status: open
title: subclass of multiprocessing Connection segfault upon attribute acces
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Python tracker <[email protected]>
<http://bugs.python.org/issue24427>
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