diff options
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2024-04-13-18-59-25.gh-issue-115874.c3xG-E.rst | 1 | ||||
| -rw-r--r-- | Modules/_asynciomodule.c | 18 |
2 files changed, 17 insertions, 2 deletions
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-04-13-18-59-25.gh-issue-115874.c3xG-E.rst b/Misc/NEWS.d/next/Core and Builtins/2024-04-13-18-59-25.gh-issue-115874.c3xG-E.rst new file mode 100644 index 0000000..5a6fa4c --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2024-04-13-18-59-25.gh-issue-115874.c3xG-E.rst @@ -0,0 +1 @@ +Fixed a possible segfault during garbage collection of ``_asyncio.FutureIter`` objects diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c index b886051..0873d32 100644 --- a/Modules/_asynciomodule.c +++ b/Modules/_asynciomodule.c @@ -1601,11 +1601,25 @@ static void FutureIter_dealloc(futureiterobject *it) { PyTypeObject *tp = Py_TYPE(it); - asyncio_state *state = get_asyncio_state_by_def((PyObject *)it); + + // FutureIter is a heap type so any subclass must also be a heap type. + assert(_PyType_HasFeature(tp, Py_TPFLAGS_HEAPTYPE)); + + PyObject *module = ((PyHeapTypeObject*)tp)->ht_module; + asyncio_state *state = NULL; + PyObject_GC_UnTrack(it); tp->tp_clear((PyObject *)it); - if (state->fi_freelist_len < FI_FREELIST_MAXLEN) { + // GH-115874: We can't use PyType_GetModuleByDef here as the type might have + // already been cleared, which is also why we must check if ht_module != NULL. + // Due to this restriction, subclasses that belong to a different module + // will not be able to use the free list. + if (module && _PyModule_GetDef(module) == &_asynciomodule) { + state = get_asyncio_state(module); + } + + if (state && state->fi_freelist_len < FI_FREELIST_MAXLEN) { state->fi_freelist_len++; it->future = (FutureObj*) state->fi_freelist; state->fi_freelist = it; |