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bpo-32710: Fix _overlapped.Overlapped memory leaks (GH-11489)

Browse source 
Fix memory leaks in asyncio ProactorEventLoop on overlapped operation
failures.

Changes:

* Implement the tp_traverse slot in the _overlapped.Overlapped type
  to help to break reference cycles and identify referrers in the
  garbage collector.
* Always clear overlapped on failure: not only set type to
  TYPE_NOT_STARTED, but release also resources.
This commit is contained in:
Victor Stinner 2019-01-11 14:35:14 +01:00 committed by GitHub
parent fd7d539be3
commit 5485085b32
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 56 additions and 24 deletions
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2
Misc/NEWS.d/next/Library/2019-01-10-15-55-10.bpo-32710.KwECPu.rst Normal file
View file

@ -0,0 +1,2 @@
Fix memory leaks in asyncio ProactorEventLoop on overlapped operation
failure.

78
Modules/overlapped.c
View file

@ -561,6 +561,28 @@ Overlapped_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
return (PyObject *)self;
}
/* Note (bpo-32710): OverlappedType.tp_clear is not defined to not release
buffers while overlapped are still running, to prevent a crash. */
static int
Overlapped_clear(OverlappedObject *self)
{
switch (self->type) {
case TYPE_READ:
case TYPE_ACCEPT:
Py_CLEAR(self->allocated_buffer);
break;
case TYPE_WRITE:
case TYPE_READINTO:
if (self->user_buffer.obj) {
PyBuffer_Release(&self->user_buffer);
}
break;
}
self->type = TYPE_NOT_STARTED;
return 0;
}
static void
Overlapped_dealloc(OverlappedObject *self)
{
@ -594,20 +616,11 @@ Overlapped_dealloc(OverlappedObject *self)
}
}
if (self->overlapped.hEvent != NULL)
if (self->overlapped.hEvent != NULL) {
CloseHandle(self->overlapped.hEvent);
switch (self->type) {
case TYPE_READ:
case TYPE_ACCEPT:
Py_CLEAR(self->allocated_buffer);
break;
case TYPE_WRITE:
case TYPE_READINTO:
if (self->user_buffer.obj)
PyBuffer_Release(&self->user_buffer);
break;
}
Overlapped_clear(self);
PyObject_Del(self);
SetLastError(olderr);
}
@ -723,8 +736,7 @@ do_ReadFile(OverlappedObject *self, HANDLE handle,
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
PyBuffer_Release(&self->user_buffer);
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -827,7 +839,7 @@ do_WSARecv(OverlappedObject *self, HANDLE handle,
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -955,7 +967,7 @@ Overlapped_WriteFile(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1012,8 +1024,7 @@ Overlapped_WSASend(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
PyBuffer_Release(&self->user_buffer);
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1063,7 +1074,7 @@ Overlapped_AcceptEx(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1155,7 +1166,7 @@ Overlapped_ConnectEx(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1194,7 +1205,7 @@ Overlapped_DisconnectEx(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1249,7 +1260,7 @@ Overlapped_TransmitFile(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_NONE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1290,7 +1301,7 @@ Overlapped_ConnectNamedPipe(OverlappedObject *self, PyObject *args)
case ERROR_IO_PENDING:
Py_RETURN_FALSE;
default:
self->type = TYPE_NOT_STARTED;
Overlapped_clear(self);
return SetFromWindowsErr(err);
}
}
@ -1340,6 +1351,25 @@ Overlapped_getpending(OverlappedObject *self)
self->type != TYPE_NOT_STARTED);
}
static int
Overlapped_traverse(OverlappedObject *self, visitproc visit, void *arg)
{
switch (self->type) {
case TYPE_READ:
case TYPE_ACCEPT:
Py_VISIT(self->allocated_buffer);
break;
case TYPE_WRITE:
case TYPE_READINTO:
if (self->user_buffer.obj) {
Py_VISIT(&self->user_buffer.obj);
}
break;
}
return 0;
}
static PyMethodDef Overlapped_methods[] = {
{"getresult", (PyCFunction) Overlapped_getresult,
METH_VARARGS, Overlapped_getresult_doc},
@ -1410,7 +1440,7 @@ PyTypeObject OverlappedType = {
/* tp_as_buffer */ 0,
/* tp_flags */ Py_TPFLAGS_DEFAULT,
/* tp_doc */ "OVERLAPPED structure wrapper",
/* tp_traverse */ 0,
/* tp_traverse */ (traverseproc)Overlapped_traverse,
/* tp_clear */ 0,
/* tp_richcompare */ 0,
/* tp_weaklistoffset */ 0,