missing dictionary deallocation in Cython's init code #557
Description
Okay, the problem I found is deep in Cython generated code and
maybe not the fault of Cython, but might be an underlying issue
in Python. For each of the 244 pyx files we have in the tree
we do not deallocate a dictionary. While this
isn't a defect per se it makes the valgrind output more noise
and therefor more difficult to parse.
The example output below is from rational.pyx. The function initrational
is created via Cython (there is no init-method, but that comes out of
the creation of the class as far as I can tell):
==25825== 3,072 bytes in 1 blocks are still reachable in loss record 2,268 of 2,539
==25825== at 0x4A05809: malloc (vg_replace_malloc.c:149)
==25825== by 0x43F179: dictresize (dictobject.c:513)
==25825== by 0x45B00C: PyType_Ready (typeobject.c:5575)
==25825== by 0x169D79A0: initrational (rational.c:10789)
==25825== by 0x49F762: _PyImport_LoadDynamicModule (importdl.c:53)
==25825== by 0x49D63E: import_submodule (import.c:2394)
==25825== by 0x49DB11: load_next (import.c:2214)
==25825== by 0x49DD6E: import_module_level (import.c:2002)
==25825== by 0x49E1A4: PyImport_ImportModuleLevel (import.c:2066)
==25825== by 0x47D5D8: builtin___import__ (bltinmodule.c:47)
==25825== by 0x4156A2: PyObject_Call (abstract.c:1860)
==25825== by 0x47DB71: PyEval_CallObjectWithKeywords (ceval.c:3433)
The exact line from rational.c:10789 is:
if (PyType_Ready(&__pyx_type_8rational_Rational) < 0) {__pyx_filename = __pyx_f[1]; __pyx_lineno = 126; goto __pyx_L1;}
It mentions line 126 which in rational.pyx is:
cdef class Rational(sage.structure.element.FieldElement):
So can be dereference the class somehow upon exit? Looking
at valgrind-sessions from python it appears that this is
possible because otherwise there would be a large number of
leak dictionaries from the buildin c-libraries.
Cheers,
Michael
Component: memleak
Issue created by migration from https://trac.sagemath.org/ticket/557