pytorch/torch/csrc/dynamo/cache_entry.cpp
William Wen ee1c2449f7 [dynamo] delete dynamo cache entry when guard function is invalidated [attempt 2] (#119107)
Attempt #2 for https://github.com/pytorch/pytorch/pull/117875 to fix https://github.com/pytorch/pytorch/issues/112090.

Summary of changes:
- ~Changed CacheEntry linked list into a doubly-linked list structure to support deletion.~ (done by C++ refactor)
- Added CacheEntry and ExtraState borrowed references to GuardFn so that GuardFn can tell ExtraState to delete CacheEntry when the GuardFn is invalidated.
- ~Added ExtraState raw reference to CacheEntry so that we can get ExtraState to correctly point to the first CacheEntry if it gets deleted.~ (done by C++ refactor)
- CacheEntry destructor needs to reset GuardFn refs to ExtraState/CacheEntry in order to prevent use-after-free.
- code_context values that are nn.GraphModules need to be weakrefs in order to prevent circular references.
- Added tests that check for memory leaks and cache deletion operations.

Pull Request resolved: https://github.com/pytorch/pytorch/pull/119107
Approved by: https://github.com/jansel
2024-02-07 03:32:42 +00:00

37 lines
986 B
C++

#include <torch/csrc/dynamo/cache_entry.h>
#include <torch/csrc/dynamo/debug_macros.h>
#include <torch/csrc/dynamo/extra_state.h>
CacheEntry::CacheEntry(const py::handle& guarded_code) {
this->check_fn = guarded_code.attr("check_fn");
this->code = guarded_code.attr("code");
}
CacheEntry::~CacheEntry() {
// prevent check_fn from use-after-free when invalidating
this->check_fn.attr("cache_entry") = py::none();
this->check_fn.attr("extra_state") = py::none();
}
py::object CacheEntry::next() {
NULL_CHECK(this->_owner);
auto it = this->_owner_loc;
++it;
if (it == this->_owner->cache_entry_list.end()) {
return py::none();
}
return py::cast(*it, py::return_value_policy::reference);
}
PyCodeObject* CacheEntry_get_code(CacheEntry* e) {
return (PyCodeObject*)e->code.ptr();
}
PyObject* CacheEntry_to_obj(CacheEntry* e) {
if (!e) {
return py::none().release().ptr();
}
return py::cast(e, py::return_value_policy::reference).release().ptr();
}