diff options
| -rw-r--r-- | Misc/NEWS | 10 | ||||
| -rw-r--r-- | Python/pystate.c | 20 |
2 files changed, 26 insertions, 4 deletions
@@ -136,6 +136,16 @@ Build C API ----- +- The C API calls ``PyInterpreterState_New()`` and ``PyThreadState_New()`` + are two of the very few advertised as being safe to call without holding + the GIL. However, this wasn't true in a debug build, as bug 1041645 + demonstrated. In a debug build, Python redirects the ``PyMem`` family + of calls to Python's small-object allocator, to get the benefit of + its extra debugging capabilities. But Python's small-object allocator + isn't threadsafe, relying on the GIL to avoid the expense of doing its + own locking. ``PyInterpreterState_New()`` and ``PyThreadState_New()`` + call the platform ``malloc()`` directly now, regardless of build type. + - PyLong_AsUnsignedLong[Mask] now support int objects as well. - SF patch #998993: ``PyUnicode_DecodeUTF8Stateful`` and diff --git a/Python/pystate.c b/Python/pystate.c index 703ce48..613f8cc 100644 --- a/Python/pystate.c +++ b/Python/pystate.c @@ -3,6 +3,16 @@ #include "Python.h" +/* -------------------------------------------------------------------------- +CAUTION + +Always use malloc() and free() directly in this file. A number of these +functions are advertised as safe to call when the GIL isn't held, and in +a debug build Python redirects (e.g.) PyMem_NEW (etc) to Python's debugging +obmalloc functions. Those aren't thread-safe (they rely on the GIL to avoid +the expense of doing their own locking). +-------------------------------------------------------------------------- */ + #ifdef HAVE_DLOPEN #ifdef HAVE_DLFCN_H #include <dlfcn.h> @@ -41,7 +51,8 @@ PyThreadFrameGetter _PyThreadState_GetFrame = NULL; PyInterpreterState * PyInterpreterState_New(void) { - PyInterpreterState *interp = PyMem_NEW(PyInterpreterState, 1); + PyInterpreterState *interp = (PyInterpreterState *) + malloc(sizeof(PyInterpreterState)); if (interp != NULL) { HEAD_INIT(); @@ -119,7 +130,7 @@ PyInterpreterState_Delete(PyInterpreterState *interp) Py_FatalError("PyInterpreterState_Delete: remaining threads"); *p = interp->next; HEAD_UNLOCK(); - PyMem_DEL(interp); + free(interp); } @@ -133,7 +144,8 @@ threadstate_getframe(PyThreadState *self) PyThreadState * PyThreadState_New(PyInterpreterState *interp) { - PyThreadState *tstate = PyMem_NEW(PyThreadState, 1); + PyThreadState *tstate = (PyThreadState *)malloc(sizeof(PyThreadState)); + if (_PyThreadState_GetFrame == NULL) _PyThreadState_GetFrame = threadstate_getframe; @@ -226,7 +238,7 @@ tstate_delete_common(PyThreadState *tstate) } *p = tstate->next; HEAD_UNLOCK(); - PyMem_DEL(tstate); + free(tstate); } |