http://trac.sagemath.org/sage_trac/ticket/8301
I just got this from m4ri:

INPUT:
   
C = Criterion(37, use_integral_structure=False)
T2=C.T(2)
T3=C.T(3)
timeit('C.is_independent([T2,T3,T3,T2])')  

OUTPUT:

*** glibc detected *** /home/wstein/sage/local/bin/python: free():
invalid next size (fast): 0x000000000758b1b0 ***
======= Backtrace: =========
/lib/libc.so.6[0x7ff8a05dedd6]
/lib/libc.so.6(cfree+0x6c)[0x7ff8a05e374c]
/home/wstein/sage/local/lib/libm4ri-0.0.20091101.so(_mzd_apply_p_right_e\
ven+0x2fb)[0x7ff882c3259b]
/home/wstein/sage/local/lib/libm4ri-0.0.20091101.so(_mzd_lqup_mmpf+0x499\
)[0x7ff882c3b199]
/home/wstein/sage/local/lib/libm4ri-0.0.20091101.so(_mzd_lqup+0xbd)[0x7f\
f882c37e3d]
/home/wstein/sage/local/lib/python2.6/site-packages/sage/matrix/matrix_m\
od2_dense.so[0x7ff882e4a8d7]
/home/wstein/sage/local/bin/python(PyEval_EvalFrameEx+0x533b)[0x4a00fb]
/home/wstein/sage/local/bin/python(PyEval_EvalFrameEx+0x5887)[0x4a0647]
/home/wstein/sage/local/bin/python(PyEval_EvalFrameEx+0x5887)[0x4a0647]
/home/wstein/sage/local/bin/python(PyEval_EvalCodeEx+0x8a0)[0x4a1920]
/home/wstein/sage/local/bin/python(PyEval_EvalFrameEx+0x4e8d)[0x49fc4d]
/home/wstein/sage/local/bin/python(PyEval_EvalCodeEx+0x8a0)[0x4a1920]
/home/wstein/sage/local/bin/python[0x4f622b]
/home/wstein/sage/local/bin/python(PyObject_Call+0x47)[0x41b457]
/home/wstein/sage/local/bin/python(PyEval_CallObjectWithKeywords+0x43)[0\
x499dd3]
/home/wstein/sage/local/lib/python2.6/site-packages/sage/misc/sage_timei\
t_class.so[0x7ff89a9ba7db]
/home/wstein/sage/local/bin/python(PyObject_Call+0x47)[0x41b457]
/home/wstein/sage/local/bin/python[0x42329f]
/home/wstein/sage/local/bin/python(PyObject_Call+0x47)[0x41b457]
/home/wstein/sage/local/bin/python(PyEval_CallObjectWithKeywords+0x43)[0\
x499dd3]