#12157: Segfault in __Pyx_check_binary_version
------------------------------+---------------------------------------------
Reporter: vbraun | Owner: jason, was
Type: defect | Status: needs_review
Priority: blocker | Milestone: sage-4.8
Component: linear algebra | Keywords:
Work_issues: | Upstream: N/A
Reviewer: Volker Braun | Author: François Bissey
Merged: | Dependencies:
------------------------------+---------------------------------------------
Changes (by newvalueoldvalue):
* reviewer: Jeroen Demeyer => Volker Braun
* author: Volker Braun => François Bissey
Comment:
{{{
(gdb) bt 5
#0 0x00019df6 in ?? ()
#1 0xb37d6484 in __Pyx_check_binary_version () at
sage/matrix/matrix_modn_dense_float.cpp:17227
#2 0xb37d105f in initmatrix_modn_dense_float () at
sage/matrix/matrix_modn_dense_float.cpp:15808
#3 0xb7f2e50c in _PyImport_LoadDynamicModule (name=0xbffca9f8
"sage.matrix.matrix_modn_dense_float",
pathname=0xbffc996b
"/home/vbraun/tesla/sage-4.8.alpha4/local/lib/python2.6/site-
packages/sage/matrix/matrix_modn_dense_float.so", fp=0x8cc69d8) at
./Python/importdl.c:53
#4 0xb7f2bf50 in load_module (name=0xbffca9f8
"sage.matrix.matrix_modn_dense_float",
fp=<optimized out>,
buf=0xbffc996b "/home/vbraun/tesla/sage-4.8.alpha4/local/lib/python2.6
/site-packages/sage/matrix/matrix_modn_dense_float.so", type=3,
loader=0x0) at Python/import.c:1828
(More stack frames follow...)
(gdb) frame 0
#0 0x00019df6 in ?? ()
(gdb) print *0x00019df6
Cannot access memory at address 0x19df6
(gdb) up
#1 0xb37d6484 in __Pyx_check_binary_version () at
sage/matrix/matrix_modn_dense_float.cpp:17227
17227 PyOS_snprintf(ctversion, 4, "%d.%d", PY_MAJOR_VERSION,
PY_MINOR_VERSION);
(gdb) disassemble
Dump of assembler code for function __Pyx_check_binary_version():
0xb37d6437 <+0>: push %ebp
0xb37d6438 <+1>: mov %esp,%ebp
0xb37d643a <+3>: push %ebx
0xb37d643b <+4>: sub $0x104,%esp
0xb37d6441 <+10>: call 0xb37b4087 <__i686.get_pc_thunk.bx>
0xb37d6446 <+15>: add $0x32bae,%ebx
0xb37d644c <+21>: mov %gs:0x14,%eax
0xb37d6452 <+27>: mov %eax,-0xc(%ebp)
0xb37d6455 <+30>: xor %eax,%eax
0xb37d6457 <+32>: movl $0x6,0x10(%esp)
0xb37d645f <+40>: movl $0x2,0xc(%esp)
0xb37d6467 <+48>: lea -0x97a9(%ebx),%eax
0xb37d646d <+54>: mov %eax,0x8(%esp)
0xb37d6471 <+58>: movl $0x4,0x4(%esp)
0xb37d6479 <+66>: lea -0x14(%ebp),%eax
0xb37d647c <+69>: mov %eax,(%esp)
0xb37d647f <+72>: call 0xb37b2df0 <PyOS_snprintf@plt>
=> 0xb37d6484 <+77>: call 0xb37b2850 <Py_GetVersion@plt>
0xb37d6489 <+82>: mov %eax,0xc(%esp)
0xb37d648d <+86>: lea -0x97a3(%ebx),%eax
}}}
It dies when calling PyOS_snprintf, it seems like something went very
wrong when trying to resolve the givaro symbols. I don't understand why
that should make Python and/or glibc symbols undefined but apparently it
does. Of course it works fine in the debugger:
{{{
(gdb) print PyOS_snprintf(ctversion, 4, "%d.%d", 2, 6)
$15 = 3
(gdb) print ctversion
$16 = "2.6"
}}}
In any case, I'm giving positive review to Francois' patch: We clearly
should link with all necessary libraries. Though I still don't understand
why it segfaults the way it does.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12157#comment:7>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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