Issue #13992: The trashcan mechanism is now thread-safe. This eliminates

sporadic crashes in multi-thread programs when several long deallocator
chains ran concurrently and involved subclasses of built-in container
types.

Note that the trashcan functions are part of the stable ABI, therefore
they have to be kept around for binary compatibility of extensions.
This commit is contained in:
Antoine Pitrou 2012-09-06 01:17:42 +02:00
commit 5b4faae307
7 changed files with 140 additions and 9 deletions

View file

@ -961,24 +961,33 @@ chain of N deallocations is broken into N / PyTrash_UNWIND_LEVEL pieces,
with the call stack never exceeding a depth of PyTrash_UNWIND_LEVEL.
*/
/* This is the old private API, invoked by the macros before 3.2.4.
Kept for binary compatibility of extensions using the stable ABI. */
PyAPI_FUNC(void) _PyTrash_deposit_object(PyObject*);
PyAPI_FUNC(void) _PyTrash_destroy_chain(void);
PyAPI_DATA(int) _PyTrash_delete_nesting;
PyAPI_DATA(PyObject *) _PyTrash_delete_later;
/* The new thread-safe private API, invoked by the macros below. */
PyAPI_FUNC(void) _PyTrash_thread_deposit_object(PyObject*);
PyAPI_FUNC(void) _PyTrash_thread_destroy_chain(void);
#define PyTrash_UNWIND_LEVEL 50
#define Py_TRASHCAN_SAFE_BEGIN(op) \
if (_PyTrash_delete_nesting < PyTrash_UNWIND_LEVEL) { \
++_PyTrash_delete_nesting;
/* The body of the deallocator is here. */
do { \
PyThreadState *_tstate = PyThreadState_GET(); \
if (_tstate->trash_delete_nesting < PyTrash_UNWIND_LEVEL) { \
++_tstate->trash_delete_nesting;
/* The body of the deallocator is here. */
#define Py_TRASHCAN_SAFE_END(op) \
--_PyTrash_delete_nesting; \
if (_PyTrash_delete_later && _PyTrash_delete_nesting <= 0) \
_PyTrash_destroy_chain(); \
} \
else \
_PyTrash_deposit_object((PyObject*)op);
--_tstate->trash_delete_nesting; \
if (_tstate->trash_delete_later && _tstate->trash_delete_nesting <= 0) \
_PyTrash_thread_destroy_chain(); \
} \
else \
_PyTrash_thread_deposit_object((PyObject*)op); \
} while (0);
#ifndef Py_LIMITED_API
PyAPI_FUNC(void)