mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-04 08:59:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 11

Issue #5437: A preallocated MemoryError instance should not hold traceback

Browse source 
data (including local variables caught in the stack trace) alive infinitely.
This commit is contained in:
Antoine Pitrou 2010-10-28 22:56:58 +00:00
parent 1842d0c4d8
commit 07e20ef50b
5 changed files with 130 additions and 34 deletions
Download patch file Download diff file Expand all files Collapse all files

97
Objects/exceptions.c
View file

@ -1777,7 +1777,91 @@ SimpleExtendsException(PyExc_Exception, ReferenceError,
/*
* MemoryError extends Exception
*/
SimpleExtendsException(PyExc_Exception, MemoryError, "Out of memory.");
#define MEMERRORS_SAVE 16
static PyBaseExceptionObject *memerrors_freelist = NULL;
static int memerrors_numfree = 0;
static PyObject *
MemoryError_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
PyBaseExceptionObject *self;
if (type != (PyTypeObject *) PyExc_MemoryError)
return BaseException_new(type, args, kwds);
if (memerrors_freelist == NULL)
return BaseException_new(type, args, kwds);
/* Fetch object from freelist and revive it */
self = memerrors_freelist;
self->args = PyTuple_New(0);
/* This shouldn't happen since the empty tuple is persistent */
if (self->args == NULL)
return NULL;
memerrors_freelist = (PyBaseExceptionObject *) self->dict;
memerrors_numfree--;
self->dict = NULL;
_Py_NewReference((PyObject *)self);
_PyObject_GC_TRACK(self);
return (PyObject *)self;
}
static void
MemoryError_dealloc(PyBaseExceptionObject *self)
{
_PyObject_GC_UNTRACK(self);
BaseException_clear(self);
if (memerrors_numfree >= MEMERRORS_SAVE)
Py_TYPE(self)->tp_free((PyObject *)self);
else {
self->dict = (PyObject *) memerrors_freelist;
memerrors_freelist = self;
memerrors_numfree++;
}
}
static void
preallocate_memerrors(void)
{
/* We create enough MemoryErrors and then decref them, which will fill
up the freelist. */
int i;
PyObject *errors[MEMERRORS_SAVE];
for (i = 0; i < MEMERRORS_SAVE; i++) {
errors[i] = MemoryError_new((PyTypeObject *) PyExc_MemoryError,
NULL, NULL);
if (!errors[i])
Py_FatalError("Could not preallocate MemoryError object");
}
for (i = 0; i < MEMERRORS_SAVE; i++) {
Py_DECREF(errors[i]);
}
}
static void
free_preallocated_memerrors(void)
{
while (memerrors_freelist != NULL) {
PyObject *self = (PyObject *) memerrors_freelist;
memerrors_freelist = (PyBaseExceptionObject *) memerrors_freelist->dict;
Py_TYPE(self)->tp_free((PyObject *)self);
}
}
static PyTypeObject _PyExc_MemoryError = {
PyVarObject_HEAD_INIT(NULL, 0)
"MemoryError",
sizeof(PyBaseExceptionObject),
0, (destructor)MemoryError_dealloc, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0,
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC,
PyDoc_STR("Out of memory."), (traverseproc)BaseException_traverse,
(inquiry)BaseException_clear, 0, 0, 0, 0, 0, 0, 0, &_PyExc_Exception,
0, 0, 0, offsetof(PyBaseExceptionObject, dict),
(initproc)BaseException_init, 0, MemoryError_new
};
PyObject *PyExc_MemoryError = (PyObject *) &_PyExc_MemoryError;
/*
* BufferError extends Exception
@ -1869,11 +1953,6 @@ SimpleExtendsException(PyExc_Warning, ResourceWarning,
/* Pre-computed MemoryError instance. Best to create this as early as
* possible and not wait until a MemoryError is actually raised!
*/
PyObject *PyExc_MemoryErrorInst=NULL;
/* Pre-computed RuntimeError instance for when recursion depth is reached.
Meant to be used when normalizing the exception for exceeding the recursion
depth will cause its own infinite recursion.
@ -2012,9 +2091,7 @@ _PyExc_Init(void)
POST_INIT(BytesWarning)
POST_INIT(ResourceWarning)
PyExc_MemoryErrorInst = BaseException_new(&_PyExc_MemoryError, NULL, NULL);
if (!PyExc_MemoryErrorInst)
Py_FatalError("Cannot pre-allocate MemoryError instance");
preallocate_memerrors();
PyExc_RecursionErrorInst = BaseException_new(&_PyExc_RuntimeError, NULL, NULL);
if (!PyExc_RecursionErrorInst)
@ -2045,6 +2122,6 @@ _PyExc_Init(void)
void
_PyExc_Fini(void)
{
Py_CLEAR(PyExc_MemoryErrorInst);
Py_CLEAR(PyExc_RecursionErrorInst);
free_preallocated_memerrors();
}