diff options
| -rw-r--r-- | Lib/test/test_memoryview.py | 26 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Core_and_Builtins/2024-11-30-23-35-45.gh-issue-127085.KLKylb.rst | 1 | ||||
| -rw-r--r-- | Objects/memoryobject.c | 33 |
3 files changed, 52 insertions, 8 deletions
diff --git a/Lib/test/test_memoryview.py b/Lib/test/test_memoryview.py index 96320eb..856e179 100644 --- a/Lib/test/test_memoryview.py +++ b/Lib/test/test_memoryview.py @@ -16,7 +16,8 @@ import pickle import struct from itertools import product -from test.support import import_helper +from test import support +from test.support import import_helper, threading_helper class MyObject: @@ -733,5 +734,28 @@ class OtherTest(unittest.TestCase): self.assertIsNone(wr()) +@threading_helper.requires_working_threading() +@support.requires_resource("cpu") +class RacingTest(unittest.TestCase): + def test_racing_getbuf_and_releasebuf(self): + """Repeatly access the memoryview for racing.""" + from multiprocessing.managers import SharedMemoryManager + from threading import Thread + + n = 100 + with SharedMemoryManager() as smm: + obj = smm.ShareableList(range(100)) + threads = [] + for _ in range(n): + # Issue gh-127085, the `ShareableList.count` is just a convenient way to mess the `exports` + # counter of `memoryview`, this issue has no direct relation with `ShareableList`. + threads.append(Thread(target=obj.count, args=(1,))) + + with threading_helper.start_threads(threads): + pass + + del obj + + if __name__ == "__main__": unittest.main() diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2024-11-30-23-35-45.gh-issue-127085.KLKylb.rst b/Misc/NEWS.d/next/Core_and_Builtins/2024-11-30-23-35-45.gh-issue-127085.KLKylb.rst new file mode 100644 index 0000000..a59b950 --- /dev/null +++ b/Misc/NEWS.d/next/Core_and_Builtins/2024-11-30-23-35-45.gh-issue-127085.KLKylb.rst @@ -0,0 +1 @@ +Fix race when exporting a buffer from a :class:`memoryview` object on the :term:`free-threaded <free threading>` build. diff --git a/Objects/memoryobject.c b/Objects/memoryobject.c index afe2dcb..ea4d24d 100644 --- a/Objects/memoryobject.c +++ b/Objects/memoryobject.c @@ -1086,6 +1086,16 @@ PyBuffer_ToContiguous(void *buf, const Py_buffer *src, Py_ssize_t len, char orde return ret; } +static inline Py_ssize_t +get_exports(PyMemoryViewObject *buf) +{ +#ifdef Py_GIL_DISABLED + return _Py_atomic_load_ssize_relaxed(&buf->exports); +#else + return buf->exports; +#endif +} + /****************************************************************************/ /* Release/GC management */ @@ -1098,7 +1108,7 @@ PyBuffer_ToContiguous(void *buf, const Py_buffer *src, Py_ssize_t len, char orde static void _memory_release(PyMemoryViewObject *self) { - assert(self->exports == 0); + assert(get_exports(self) == 0); if (self->flags & _Py_MEMORYVIEW_RELEASED) return; @@ -1119,15 +1129,16 @@ static PyObject * memoryview_release_impl(PyMemoryViewObject *self) /*[clinic end generated code: output=d0b7e3ba95b7fcb9 input=bc71d1d51f4a52f0]*/ { - if (self->exports == 0) { + Py_ssize_t exports = get_exports(self); + if (exports == 0) { _memory_release(self); Py_RETURN_NONE; } - if (self->exports > 0) { + if (exports > 0) { PyErr_Format(PyExc_BufferError, - "memoryview has %zd exported buffer%s", self->exports, - self->exports==1 ? "" : "s"); + "memoryview has %zd exported buffer%s", exports, + exports==1 ? "" : "s"); return NULL; } @@ -1140,7 +1151,7 @@ static void memory_dealloc(PyObject *_self) { PyMemoryViewObject *self = (PyMemoryViewObject *)_self; - assert(self->exports == 0); + assert(get_exports(self) == 0); _PyObject_GC_UNTRACK(self); _memory_release(self); Py_CLEAR(self->mbuf); @@ -1161,7 +1172,7 @@ static int memory_clear(PyObject *_self) { PyMemoryViewObject *self = (PyMemoryViewObject *)_self; - if (self->exports == 0) { + if (get_exports(self) == 0) { _memory_release(self); Py_CLEAR(self->mbuf); } @@ -1589,7 +1600,11 @@ memory_getbuf(PyObject *_self, Py_buffer *view, int flags) view->obj = Py_NewRef(self); +#ifdef Py_GIL_DISABLED + _Py_atomic_add_ssize(&self->exports, 1); +#else self->exports++; +#endif return 0; } @@ -1598,7 +1613,11 @@ static void memory_releasebuf(PyObject *_self, Py_buffer *view) { PyMemoryViewObject *self = (PyMemoryViewObject *)_self; +#ifdef Py_GIL_DISABLED + _Py_atomic_add_ssize(&self->exports, -1); +#else self->exports--; +#endif return; /* PyBuffer_Release() decrements view->obj after this function returns. */ } |