Ticket #833 (closed defect: fixed)

Opened 3 years ago

Last modified 3 years ago

[with patch] new coercion model segfault (??)

Reported by: was Owned by: robertwb
Priority: blocker Milestone: sage-2.8.7
Component: basic arithmetic Keywords:
Cc: Author(s):
Report Upstream: Reviewer(s):
Merged in: Work issues:

Description 

sage: singular('2')*3


------------------------------------------------------------
Unhandled SIGSEGV: A segmentation fault occured in SAGE.
This probably occured because a *compiled* component
of SAGE has a bug in it (typically accessing invalid memory)
or is not properly wrapped with _sig_on, _sig_off.
You might want to run SAGE under gdb with 'sage -gdb' to debug this.
SAGE will now terminate (sorry).
------------------------------------------------------------

Attachments

cython-fix.patch Download (1.5 KB) - added by cwitty 3 years ago.
This is the patch I applied to the Cython spkg (to the inner hg repository). I'm only posting this for completeness; you want to download the spkg instead.

Change History

Changed 3 years ago by mabshoff

I got a backtrace from sage.math: 

(gdb) bt
#0  0x0000000000425343 in BaseException_dealloc (self=0x2b4d4914c950) at Objects/exceptions.c:84
#1  0x000000000043e5cb in insertdict (mp=0x65a0b0, key=0x2b4d394d53e8, hash=7943982932492106152,
    value=0x2b4d46ae0638) at Objects/dictobject.c:412
#2  0x000000000043ff8c in PyDict_SetItem (op=0x65a0b0, key=0x2b4d394d53e8, value=0x2b4d46ae0638)
    at Objects/dictobject.c:637
#3  0x000000000044008b in PyDict_SetItemString (v=0x65a0b0, key=<value optimized out>, item=0x2b4d46ae0638)
    at Objects/dictobject.c:2178
#4  0x0000000000483242 in PyEval_EvalFrameEx (f=0xf7e630, throwflag=<value optimized out>)
    at Python/ceval.c:2952
#5  0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3be908a0, globals=<value optimized out>,
    locals=<value optimized out>, args=0x2b4d4913aae8, argcount=1, kws=0x0, kwcount=0, defs=0x0,
    defcount=0, closure=0x0) at Python/ceval.c:2831
#6  0x00000000004ce528 in function_call (func=0x2b4d3c1e0488, arg=0x2b4d4913aad0, kw=0x0)
    at Objects/funcobject.c:517
#7  0x0000000000415523 in PyObject_Call (func=0x2b4d4914c950, arg=0x2b4d394d53e8, kw=0x0)
    at Objects/abstract.c:1860
#8  0x000000000041bc43 in instancemethod_call (func=<value optimized out>, arg=0x2b4d4913aad0, kw=0x0)
    at Objects/classobject.c:2497
#9  0x0000000000415523 in PyObject_Call (func=0x2b4d4914c950, arg=0x2b4d394d53e8, kw=0x0)
    at Objects/abstract.c:1860
#10 0x000000000047c851 in PyEval_CallObjectWithKeywords (func=0x2b4d497a3e10, arg=0x2b4d387ba050, kw=0x0)
    at Python/ceval.c:3433
#11 0x000000000045e706 in slot_tp_del (self=0x2b4d497ba4b0) at Objects/typeobject.c:4928
#12 0x000000000045542c in subtype_dealloc (self=0x2b4d497ba4b0) at Objects/typeobject.c:664
#13 0x00000000004cd268 in frame_dealloc (f=0xf2f9a0) at Objects/frameobject.c:416
#14 0x00000000004ac94b in tb_dealloc (tb=0x2b4d4914cc20) at Python/traceback.c:34
#15 0x00000000004ac957 in tb_dealloc (tb=0x2b4d46da0758) at Python/traceback.c:33
#16 0x00000000004ac957 in tb_dealloc (tb=0x2b4d4914c950) at Python/traceback.c:33
#17 0x00002b4d3c30770f in __Pyx_GetExcValue () at sage/structure/parent.c:6601
#18 0x00002b4d3c315bd1 in __pyx_f_6parent_6Parent_get_action_c_impl (__pyx_v_self=0x2b4d3ebf11f0,
    __pyx_v_S=0x2b4d3ebf2150, __pyx_v_op=0x2b4d394b76c8, __pyx_v_self_on_left=0)
    at sage/structure/parent.c:2710
#19 0x00002b4d3c30d398 in __pyx_f_6parent_6Parent_get_action_c (__pyx_v_self=0x2b4d3ebf11f0,
    __pyx_v_S=0x2b4d3ebf2150, __pyx_v_op=0x2b4d394b76c8, __pyx_v_self_on_left=0)
    at sage/structure/parent.c:1637
#20 0x00002b4d3c6902e9 in __pyx_f_6coerce_24CoercionModel_cache_maps_discover_action_c (
    __pyx_v_self=0x2b4d3c1d5bd8, __pyx_v_R=0x2b4d3ebf2150, __pyx_v_S=0x2b4d3ebf11f0,
    __pyx_v_op=0x2b4d394b76c8) at sage/structure/coerce.c:5022
#21 0x00002b4d3c68c95a in __pyx_f_6coerce_24CoercionModel_cache_maps_get_action_c (
    __pyx_v_self=0x2b4d3c1d5bd8, __pyx_v_R=0x2b4d3ebf2150, __pyx_v_S=0x2b4d3ebf11f0,
    __pyx_v_op=0x2b4d394b76c8) at sage/structure/coerce.c:4541
#22 0x00002b4d3c6a0d14 in __pyx_f_6coerce_24CoercionModel_cache_maps_bin_op_c (__pyx_v_self=0x2b4d3c1d5bd8,
    __pyx_v_x=0x2b4d497ba3c0, __pyx_v_y=0x2b4d4914e5d0, __pyx_v_op=0x2b4d394b76c8)
    at sage/structure/coerce.c:3208
#23 0x00002b4d3c4343e8 in __pyx_f_7element_11RingElement___mul__ (__pyx_v_self=0x2b4d497ba3c0,
    __pyx_v_right=0x2b4d4914e5d0) at sage/structure/element.c:8006
#24 0x0000000000415523 in PyObject_Call (func=0x2b4d4914c950, arg=0x2b4d394d53e8, kw=0x0)
    at Objects/abstract.c:1860
#25 0x000000000045ed65 in call_maybe (o=0x2b4d497ba3c0, name=<value optimized out>,
    nameobj=<value optimized out>, format=0x4e642a "(O)") at Objects/typeobject.c:967
#26 0x0000000000460703 in slot_nb_multiply (self=0x2b4d497ba3c0, other=0x2b4d4914e5d0)
    at Objects/typeobject.c:4312
#27 0x00000000004157ed in binary_op1 (v=0x2b4d46d83284, w=0x2b4d394d53e8, op_slot=16)
    at Objects/abstract.c:398
#28 0x0000000000418f28 in PyNumber_Multiply (v=0x2b4d4914c950, w=0x2b4d394d53e8) at Objects/abstract.c:669
#29 0x000000000047f98d in PyEval_EvalFrameEx (f=0x16ccdb0, throwflag=<value optimized out>)
    at Python/ceval.c:1072
#30 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d4914a0a8, globals=<value optimized out>,
    locals=<value optimized out>, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0,
    closure=0x0) at Python/ceval.c:2831
#31 0x0000000000483cc5 in PyEval_EvalFrameEx (f=0x16d0d80, throwflag=<value optimized out>)
    at Python/ceval.c:494
#32 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3bbeea80, globals=<value optimized out>,
    locals=<value optimized out>, args=0x16c57f0, argcount=2, kws=0x16c5800, kwcount=0, defs=0x0,
    defcount=0, closure=0x0) at Python/ceval.c:2831
#33 0x000000000048365d in PyEval_EvalFrameEx (f=0x16c5650, throwflag=<value optimized out>)
    at Python/ceval.c:3660
#34 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3bbee990, globals=<value optimized out>,
    locals=<value optimized out>, args=0x1, argcount=3, kws=0x16c9750, kwcount=0, defs=0x2b4d3bd5d848,
    defcount=2, closure=0x0) at Python/ceval.c:2831
#35 0x000000000048365d in PyEval_EvalFrameEx (f=0x16c95a0, throwflag=<value optimized out>)
    at Python/ceval.c:3660
#36 0x000000000048403b in PyEval_EvalFrameEx (f=0x16c3ff0, throwflag=<value optimized out>)
    at Python/ceval.c:3650
#37 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3bbee4e0, globals=<value optimized out>,
    locals=<value optimized out>, args=0x16c3748, argcount=2, kws=0x16c3758, kwcount=0,
    defs=0x2b4d3bd60b68, defcount=1, closure=0x0) at Python/ceval.c:2831
#38 0x000000000048365d in PyEval_EvalFrameEx (f=0x16c35c0, throwflag=<value optimized out>)
    at Python/ceval.c:3660
#39 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3bbee378, globals=<value optimized out>,
    locals=<value optimized out>, args=0x7cee10, argcount=2, kws=0x7cee20, kwcount=0, defs=0x2b4d3bd60b28,
    defcount=1, closure=0x0) at Python/ceval.c:2831
#40 0x000000000048365d in PyEval_EvalFrameEx (f=0x7cec80, throwflag=<value optimized out>)
    at Python/ceval.c:3660
#41 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3b982e40, globals=<value optimized out>,
    locals=<value optimized out>, args=0x2, argcount=1, kws=0x6cf790, kwcount=2, defs=0x2b4d3b99c338,
    defcount=2, closure=0x0) at Python/ceval.c:2831
#42 0x000000000048365d in PyEval_EvalFrameEx (f=0x6cf600, throwflag=<value optimized out>)
    at Python/ceval.c:3660
#43 0x0000000000484f3b in PyEval_EvalCodeEx (co=0x2b4d3881b918, globals=<value optimized out>,
    locals=<value optimized out>, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, defcount=0,
    closure=0x0) at Python/ceval.c:2831
#44 0x00000000004851d2 in PyEval_EvalCode (co=0x2b4d4914c950, globals=0x2b4d394d53e8, locals=0x0)
    at Python/ceval.c:494
#45 0x00000000004a648e in PyRun_FileExFlags (fp=0x6b8030,
    filename=0x7fff72308d43 "/tmp/Work-mabshoff/sage-2.8.5.1/local/bin/sage-gdb-pythonstartup",
    start=<value optimized out>, globals=0x672300, locals=0x672300, closeit=0, flags=0x7fff72306400)
    at Python/pythonrun.c:1271
#46 0x00000000004a6720 in PyRun_SimpleFileExFlags (fp=0x6b8030,
    filename=0x7fff72308d43 "/tmp/Work-mabshoff/sage-2.8.5.1/local/bin/sage-gdb-pythonstartup", closeit=0,
    flags=0x7fff72306400) at Python/pythonrun.c:877
#47 0x000000000041231a in Py_Main (argc=<value optimized out>, argv=<value optimized out>)
    at Modules/main.c:134
#48 0x00002b4d38d724ca in __libc_start_main () from /lib/libc.so.6
#49 0x000000000041163a in _start () at ../sysdeps/x86_64/elf/start.S:113

Cheers,

Michael

Changed 3 years ago by was

  • owner changed from somebody to robertwb
  • milestone changed from sage-2.8.6 to sage-2.8.7

Changed 3 years ago by was

  • milestone changed from sage-2.8.7 to sage-2.8.8

This is stumping us for now! :-(

Changed 3 years ago by cwitty

Here's another backtrace: 

#0  PyObject_Malloc (nbytes=34) at Objects/obmalloc.c:747
#1  0x08093527 in PyString_FromString (str=0xb7042f24 "action.pyx")
    at Objects/stringobject.c:130
#2  0xb703a5c4 in __Pyx_AddTraceback (
    funcname=0xb7042b9f "action.Action._call_c")
    at sage/categories/action.c:4319
#3  0xb704110d in __pyx_f_6action_6Action__call_c (__pyx_v_self=0x8b6ddac, 
    __pyx_v_a=0x8adf054, __pyx_v_b=0x8a6b740) at sage/categories/action.c:1120
#4  0xb7062b4c in __pyx_f_py_6coerce_17RightModuleAction___init__ (
    __pyx_v_self=0x8b6ddac, __pyx_args=0x9655dec, __pyx_kwds=0x0)
    at sage/structure/coerce.c:11026
#5  0x0809ecb4 in type_call (type=0xb7071700, args=0x9655dec, kwds=0x0)
    at Objects/typeobject.c:436
#6  0x0805c877 in PyObject_Call (func=0x8ae8000, arg=0x9655dec, kw=0x0)
    at Objects/abstract.c:1860
#7  0x080c0d2c in PyEval_CallObjectWithKeywords (func=0xb7071700, 
    arg=0x9655dec, kw=0x0) at Python/ceval.c:3433
#8  0x0805cd20 in PyObject_CallObject (o=0xb7071700, a=0x9655dec)
    at Objects/abstract.c:1851
#9  0xb70d99b6 in __pyx_f_6parent_6Parent_get_action_c_impl (
    __pyx_v_self=0xb700a36c, __pyx_v_S=0xb6ff4b24, __pyx_v_op=0xb7de426c, 
    __pyx_v_self_on_left=1) at sage/structure/parent.c:2503
#10 0xb70d4b9e in __pyx_f_py_6parent_6Parent_get_action_impl (
    __pyx_v_self=0xb700a36c, __pyx_args=0x8b93e64, __pyx_kwds=0x0)
    at sage/structure/parent.c:1790
#11 0x0805c877 in PyObject_Call (func=0x8ae8000, arg=0x8b93e64, kw=0x0)
    at Objects/abstract.c:1860
#12 0x080c0d2c in PyEval_CallObjectWithKeywords (func=0x9655fcc, 
    arg=0x8b93e64, kw=0x0) at Python/ceval.c:3433
#13 0x0805cd20 in PyObject_CallObject (o=0x9655fcc, a=0x8b93e64)
    at Objects/abstract.c:1851
#14 0xb70d1cbf in __pyx_f_6parent_6Parent_get_action_c (
    __pyx_v_self=0xb700a36c, __pyx_v_S=0xb6ff4b24, __pyx_v_op=0xb7de426c, 
    __pyx_v_self_on_left=1) at sage/structure/parent.c:1641
#15 0xb70563c5 in __pyx_f_6coerce_24CoercionModel_cache_maps_discover_action_c
    (__pyx_v_self=0xb712c50c, __pyx_v_R=0xb700a36c, __pyx_v_S=0xb6ff4b24, 
    __pyx_v_op=0xb7de426c) at sage/structure/coerce.c:6409
#16 0xb7056805 in __pyx_f_6coerce_24CoercionModel_cache_maps_discover_action_c
    (__pyx_v_self=0xb712c50c, __pyx_v_R=0xb700a36c, __pyx_v_S=0x8141b40, 
    __pyx_v_op=0xb7de426c) at sage/structure/coerce.c:6933
#17 0xb704d8d7 in __pyx_f_6coerce_24CoercionModel_cache_maps_get_action_c (
    __pyx_v_self=0xb712c50c, __pyx_v_R=0xb700a36c, __pyx_v_S=0x8141b40, 
    __pyx_v_op=0xb7de426c) at sage/structure/coerce.c:6261
#18 0xb7065fab in __pyx_f_6coerce_24CoercionModel_cache_maps_bin_op_c (
    __pyx_v_self=0xb712c50c, __pyx_v_x=0x965a20c, __pyx_v_y=0x816b088, 
    __pyx_v_op=0xb7de426c) at sage/structure/coerce.c:4515
#19 0xb70b1785 in __pyx_f_py_7element_11RingElement___mul__ (
    __pyx_v_self=0x965a20c, __pyx_v_right=0x816b088)
    at sage/structure/element.c:7603
#20 0x0805c877 in PyObject_Call (func=0x8ae8000, arg=0xb71b2a8c, kw=0x0)
    at Objects/abstract.c:1860
#21 0x080a3fbe in call_maybe (o=0x965a20c, name=0x81221f9 "__mul__", 
    nameobj=0x81621d8, format=0x812731a "(O)") at Objects/typeobject.c:967
#22 0x080a58d7 in slot_nb_multiply (self=0x965a20c, other=0x816b088)
    at Objects/typeobject.c:4312
#23 0x0805ce03 in binary_op1 (v=0x965a20c, w=0xff000000, op_slot=8)
    at Objects/abstract.c:398
#24 0x0805e823 in PyNumber_Multiply (v=0x965a20c, w=0x816b088)
    at Objects/abstract.c:669
#25 0x080c3694 in PyEval_EvalFrameEx (f=0x81746d4, throwflag=0)
    at Python/ceval.c:1072
#26 0x080c9298 in PyEval_EvalCodeEx (co=0xb7e32f98, globals=0xb7e0eacc, 
    locals=0xb7e0eacc, args=0x0, argcount=0, kws=0x0, kwcount=0, defs=0x0, 
    defcount=0, closure=0x0) at Python/ceval.c:2831
#27 0x080c93e7 in PyEval_EvalCode (co=0xb7e32f98, globals=0xb7e0eacc, 
    locals=0xb7e0eacc) at Python/ceval.c:494
#28 0x080e7fd8 in PyRun_FileExFlags (fp=0x8167008, 
    filename=0xbfdc536a "/home/cwitty/my-sage/bust.py", start=257, 
    globals=0xb7e0eacc, locals=0xb7e0eacc, closeit=1, flags=0xbfdc4678)
    at Python/pythonrun.c:1271
#29 0x080e8279 in PyRun_SimpleFileExFlags (fp=0x8167008, 
    filename=0xbfdc536a "/home/cwitty/my-sage/bust.py", closeit=1, 
    flags=0xbfdc4678) at Python/pythonrun.c:877
#30 0x08059265 in Py_Main (argc=1, argv=0xbfdc4744) at Modules/main.c:523
#31 0x08058722 in main (argc=101, argv=0x2) at ./Modules/python.c:23

This is from Starting program: /home/cwitty/pre-sage/local/bin/python /home/cwitty/my-sage/bust.py, where bust.py is: 

from sage.all import *

singular('2') * 3

Changed 3 years ago by mabshoff

Something else that is off: 

[mabshoff@localhost sage-2.8.7-alpha0]$ ./sage
----------------------------------------------------------------------
| SAGE Version 2.8.7-alpha0, Release Date: 2007-10-13                |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------

LeftModuleAction
sage: a=Singular('2')
sage: b=Integer(2)
sage: type(a)
<class 'sage.interfaces.singular.Singular'>
sage: type(b)
<type 'sage.rings.integer.Integer'>
sage: a*b
---------------------------------------------------------------------------
<type 'exceptions.TypeError'>             Traceback (most recent call last)

/tmp/Work2/sage-2.8.7-alpha0/<ipython console> in <module>()

/tmp/Work2/sage-2.8.7-alpha0/element.pyx in element.RingElement.__mul__()

/tmp/Work2/sage-2.8.7-alpha0/coerce.pyx in coerce.CoercionModel_cache_maps.bin_op_c()

/tmp/Work2/sage-2.8.7-alpha0/coerce.pxi in coerce.parent_c()

/tmp/Work2/sage-2.8.7-alpha0/local/lib/python2.5/site-packages/sage/interfaces/expect.py in __call__(self, *args)
    870
    871     def __call__(self, *args):
--> 872         return self._parent.function_call(self._name, list(args))
    873
    874

/tmp/Work2/sage-2.8.7-alpha0/local/lib/python2.5/site-packages/sage/interfaces/expect.py in function_call(self, function, args)
    832             if not isinstance(args[i], ExpectElement):
    833                 args[i] = self.new(args[i])
--> 834         return self.new("%s(%s)"%(function, ",".join([s.name() for s in args])))
    835
    836     def call(self, function_name, *args):

/tmp/Work2/sage-2.8.7-alpha0/local/lib/python2.5/site-packages/sage/interfaces/expect.py in new(self, code)
    734
    735     def new(self, code):
--> 736         return self(code)
    737
    738     ###################################################################

/tmp/Work2/sage-2.8.7-alpha0/local/lib/python2.5/site-packages/sage/interfaces/singular.py in __call__(self, x, type)
    429             x = str(x)[1:-1]
    430
--> 431         return SingularElement(self, type, x, False)
    432
    433

/tmp/Work2/sage-2.8.7-alpha0/local/lib/python2.5/site-packages/sage/interfaces/singular.py in __init__(self, parent, type, value, is_name)
    750             except (RuntimeError, TypeError, KeyboardInterrupt), x:
    751                 self._session_number = -1
--> 752                 raise TypeError, x
    753         else:
    754             self._name = value

<type 'exceptions.TypeError'>: error evaluating "def sage0=parent();":
an integer is required

Cheers,

Michael

Changed 3 years ago by mabshoff

Sorry for the above noise, please disregard it.

But: 

----------------------------------------------------------------------
| SAGE Version 2.8.7-alpha0, Release Date: 2007-10-13                |
| Type notebook() for the GUI, and license() for information.        |
----------------------------------------------------------------------
sage: a=singular('2')
[Detaching after fork from child process 27136.]
[Detaching after fork from child process 27137.]
sage: b=Integer(2)
sage: type(a)
<class 'sage.interfaces.singular.SingularElement'>
sage: type(b)
<type 'sage.rings.integer.Integer'>
sage: a*b
LeftModuleAction

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1208269120 (LWP 27124)]
PyObject_Malloc (nbytes=34) at Objects/obmalloc.c:747
747     Objects/obmalloc.c: No such file or directory.
        in Objects/obmalloc.c
(gdb) bt
#0  PyObject_Malloc (nbytes=34) at Objects/obmalloc.c:747
#1  0x080911eb in PyString_FromString (str=0x96c887 "parent.pyx") at Objects/stringobject.c:130
#2  0x0095b8c4 in __Pyx_AddTraceback (funcname=0x96c611 "parent.get_action_c_impl") at sage/structure/parent.c:7082
#3  0x0096aa24 in __pyx_f_6parent_6Parent_get_action_c_impl (__pyx_v_self=0x8a074ec, __pyx_v_S=0x89dc714,
    __pyx_v_op=0xb7f6378c, __pyx_v_self_on_left=1) at sage/structure/parent.c:2557
#4  0x00961c9c in __pyx_f_py_6parent_6Parent_get_action_impl (__pyx_v_self=0x8a074ec, __pyx_args=0x9353e8c, __pyx_kwds=0x0)
    at sage/structure/parent.c:1790
#5  0x0805a277 in PyObject_Call (func=0x9360000, arg=0x9353e8c, kw=0x0) at Objects/abstract.c:1860
#6  0x080be7cc in PyEval_CallObjectWithKeywords (func=0x9e5d9ec, arg=0x9353e8c, kw=0x0) at Python/ceval.c:3433
#7  0x0805a490 in PyObject_CallObject (o=0x9e5d9ec, a=0x9353e8c) at Objects/abstract.c:1851
#8  0x0095f90f in __pyx_f_6parent_6Parent_get_action_c (__pyx_v_self=0x8a074ec, __pyx_v_S=0x89dc714,
    __pyx_v_op=0xb7f6378c, __pyx_v_self_on_left=1) at sage/structure/parent.c:1641
#9  0x00a015b5 in __pyx_f_6coerce_24CoercionModel_cache_maps_discover_action_c (__pyx_v_self=0x89a26ac,
    __pyx_v_R=0x8a074ec, __pyx_v_S=0x89dc714, __pyx_v_op=0xb7f6378c) at sage/structure/coerce.c:6409
#10 0x009f95d7 in __pyx_f_6coerce_24CoercionModel_cache_maps_get_action_c (__pyx_v_self=0x89a26ac, __pyx_v_R=0x8a074ec,
    __pyx_v_S=0x89dc714, __pyx_v_op=0xb7f6378c) at sage/structure/coerce.c:6261
#11 0x00a1248f in __pyx_f_6coerce_24CoercionModel_cache_maps_bin_op_c (__pyx_v_self=0x89a26ac, __pyx_v_x=0x9df4144,
    __pyx_v_y=0x9defe80, __pyx_v_op=0xb7f6378c) at sage/structure/coerce.c:4515
#12 0x0099b585 in __pyx_f_py_7element_11RingElement___mul__ (__pyx_v_self=0x9df4144, __pyx_v_right=0x9defe80)
    at sage/structure/element.c:7603
#13 0x0805a277 in PyObject_Call (func=0x9360000, arg=0x9e5d44c, kw=0x0) at Objects/abstract.c:1860
#14 0x080a1b50 in call_maybe (o=0x9df4144, name=0x811f71f "__mul__", nameobj=0x815f7b8, format=0x81247fa "(O)")
    at Objects/typeobject.c:967
#15 0x080a338a in slot_nb_multiply (self=0x9df4144, other=0x9defe80) at Objects/typeobject.c:4312
#16 0x0805a573 in binary_op1 (v=0x9df4144, w=0xffff0000, op_slot=8) at Objects/abstract.c:398
#17 0x0805d8f3 in PyNumber_Multiply (v=0x9df4144, w=0x9defe80) at Objects/abstract.c:669
#18 0x080c1e7e in PyEval_EvalFrameEx (f=0x9eca184, throwflag=0) at Python/ceval.c:1072
#19 0x080c65d5 in PyEval_EvalCodeEx (co=0x9df1920, globals=0x9de6cec, locals=0x9de6cec, args=0x0, argcount=0, kws=0x0,
    kwcount=0, defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2831
#20 0x080c5852 in PyEval_EvalFrameEx (f=0x9e9af7c, throwflag=0) at Python/ceval.c:494
#21 0x080c65d5 in PyEval_EvalCodeEx (co=0xb7b77a40, globals=0xb7b6d824, locals=0x0, args=0x9e54e10, argcount=2,
    kws=0x9e54e18, kwcount=0, defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2831
#22 0x080c4a89 in PyEval_EvalFrameEx (f=0x9e54cc4, throwflag=0) at Python/ceval.c:3660
#23 0x080c65d5 in PyEval_EvalCodeEx (co=0xb7b779b0, globals=0xb7b6d824, locals=0x0, args=0x9e58e74, argcount=3,
    kws=0x9e58e80, kwcount=0, defs=0x893c2d8, defcount=2, closure=0x0) at Python/ceval.c:2831
#24 0x080c4a89 in PyEval_EvalFrameEx (f=0x9e58d2c, throwflag=0) at Python/ceval.c:3660
---Type <return> to continue, or q <return> to quit---
#25 0x080c57c5 in PyEval_EvalFrameEx (f=0x9e9b324, throwflag=0) at Python/ceval.c:3650
#26 0x080c65d5 in PyEval_EvalCodeEx (co=0xb7b77728, globals=0xb7b6d824, locals=0x0, args=0x9e547cc, argcount=2,
    kws=0x9e547d4, kwcount=0, defs=0x893c638, defcount=1, closure=0x0) at Python/ceval.c:2831
#27 0x080c4a89 in PyEval_EvalFrameEx (f=0x9e5468c, throwflag=0) at Python/ceval.c:3660
#28 0x080c65d5 in PyEval_EvalCodeEx (co=0xb7b77650, globals=0xb7b6d824, locals=0x0, args=0x88980f8, argcount=2,
    kws=0x8898100, kwcount=0, defs=0x893c618, defcount=1, closure=0x0) at Python/ceval.c:2831
#29 0x080c4a89 in PyEval_EvalFrameEx (f=0x8897fb4, throwflag=0) at Python/ceval.c:3660
#30 0x080c65d5 in PyEval_EvalCodeEx (co=0xb7bc5380, globals=0xb7bc2604, locals=0x0, args=0x87f5dfc, argcount=1,
    kws=0x87f5e00, kwcount=2, defs=0xb7b52bb8, defcount=2, closure=0x0) at Python/ceval.c:2831
#31 0x080c4a89 in PyEval_EvalFrameEx (f=0x87f5cc4, throwflag=0) at Python/ceval.c:3660
#32 0x080c65d5 in PyEval_EvalCodeEx (co=0xb7f3a608, globals=0xb7f8cacc, locals=0xb7f8cacc, args=0x0, argcount=0, kws=0x0,
    kwcount=0, defs=0x0, defcount=0, closure=0x0) at Python/ceval.c:2831
#33 0x080c6647 in PyEval_EvalCode (co=0xb7f3a608, globals=0xb7f8cacc, locals=0xb7f8cacc) at Python/ceval.c:494
#34 0x080e52c8 in PyRun_FileExFlags (fp=0x879a068,
    filename=0xbfe45c97 "/tmp/Work2/sage-2.8.7-alpha0/local/bin/sage-gdb-pythonstartup", start=257, globals=0xb7f8cacc,
    locals=0xb7f8cacc, closeit=0, flags=0xbfe44d58) at Python/pythonrun.c:1271
#35 0x080e5557 in PyRun_SimpleFileExFlags (fp=0x879a068,
    filename=0xbfe45c97 "/tmp/Work2/sage-2.8.7-alpha0/local/bin/sage-gdb-pythonstartup", closeit=0, flags=0xbfe44d58)
    at Python/pythonrun.c:877
#36 0x080571a6 in Py_Main (argc=0, argv=0xbfe44e24) at Modules/main.c:134
#37 0x08056432 in main (argc=101, argv=0x2) at ./Modules/python.c:23
(gdb)
(gdb) quit
The program is running.  Exit anyway? (y or n) y
[mabshoff@localhost sage-2.8.7-alpha0]$

Changed 3 years ago by cwitty

  • summary changed from new coercion model segfault (??) to [with patch] new coercion model segfault (??)
  • milestone changed from sage-2.8.8 to sage-2.8.7

I think this spkg may fix the problem:

 http://sage.math.washington.edu/home/cwitty/cython-0.9.6.7-p1.spkg

Cython copies a buggy chunk of C code into target files; the bug would be triggered if the last reference to some object was through a Python traceback object, and running the object's __del__ method threw and caught an exception, and the next exception after the one that created the traceback object that holds the last reference to the object is caught by a Cython method. So not very often, but it looks like the new coercion code does it.

Changed 3 years ago by cwitty

This is the patch I applied to the Cython spkg (to the inner hg repository). I'm only posting this for completeness; you want to download the spkg instead.

Changed 3 years ago by cwitty

Let me try to explain the bug circumstances again; this time I'll use more than one sentence.

Suppose you have an object A, such that A's __del__ method (or something it calls) raises and catches an exception. Also suppose that the last reference to A is somehow held by a traceback object. Now, when the traceback object gets destroyed, A's __del__ method will get called; the exception handling in this method will involve looking at the current exception in the Python thread state.

If the last reference to this traceback is in the Python thread state, and a new exception is raised and caught by Cython code, then the buggy Cython code will destroy the old traceback in an unsafe way, so that when the __del__ method looks at the current exception it will see garbage (probably triggering a double-free).

Changed 3 years ago by mabshoff

The new Cython.spkg fixes the issue for me.

Cheers,

Michael

Changed 3 years ago by mabshoff

And on sage.math the new cython also fixes the issue.

Cheers,

Michael

Changed 3 years ago by was

  • status changed from new to closed
  • resolution set to fixed

Yeah! Great work guys.

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