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bpo-36139: release GIL around munmap() #12073

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Merged
benjaminp merged 6 commits into from
Mar 6, 2019
Merged

bpo-36139: release GIL around munmap() #12073

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99eb64e
release GIL around munmap()
sorcio Feb 27, 2019
b4180d4
always release gil on mmap closure
sorcio Mar 1, 2019
9fc0e21
safely release gil on mmap closure
sorcio Mar 5, 2019
c0fc049
📜🤖 Added by blurb_it.
blurb-it[bot] Mar 6, 2019
5e3aead
fix formatting
sorcio Mar 6, 2019
d632256
news entry
sorcio Mar 6, 2019
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1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Library/2019-03-06-13-07-29.bpo-36139.6kedum.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Release GIL when closing :class:`~mmap.mmap` objects.
39 changes: 25 additions & 14 deletions Modules/mmapmodule.c
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Original file line number Diff line number Diff line change
Expand Up @@ -117,6 +117,7 @@ typedef struct {
static void
mmap_object_dealloc(mmap_object *m_obj)
{
Py_BEGIN_ALLOW_THREADS
#ifdef MS_WINDOWS
if (m_obj->data != NULL)
UnmapViewOfFile (m_obj->data);

@vstinner vstinner Mar 6, 2019

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PyMem_Free(m_obj->tagname) is called below without holding the GIL: that's illegal. Other move the call to free when the GIL is hold again, or use PyMem_RawFree().

"Warning: The GIL must be held when using these functions. "
https://docs.python.org/dev/c-api/memory.html#memory-interface

Note: You can use PYTHONMALLOC=debug or -X dev to reproduce the issue on a Python compiled in release mode.

Expand All @@ -135,6 +136,7 @@ mmap_object_dealloc(mmap_object *m_obj)
munmap(m_obj->data, m_obj->size);
}
#endif /* UNIX */
Py_END_ALLOW_THREADS

if (m_obj->weakreflist != NULL)
PyObject_ClearWeakRefs((PyObject *) m_obj);
Expand All @@ -157,28 +159,37 @@ mmap_close_method(mmap_object *self, PyObject *unused)
again.
TODO - should we check for errors in the close operations???
*/
if (self->data != NULL) {
UnmapViewOfFile(self->data);
self->data = NULL;
HANDLE map_handle = self->map_handle;
HANDLE file_handle = self->file_handle;
char *data = self->data;
self->map_handle = NULL;
self->file_handle = INVALID_HANDLE_VALUE;
self->data = NULL;
Py_BEGIN_ALLOW_THREADS
if (data != NULL) {
UnmapViewOfFile(data);
}
if (self->map_handle != NULL) {
CloseHandle(self->map_handle);
self->map_handle = NULL;
if (map_handle != NULL) {
CloseHandle(map_handle);
}
if (self->file_handle != INVALID_HANDLE_VALUE) {
CloseHandle(self->file_handle);
self->file_handle = INVALID_HANDLE_VALUE;
if (file_handle != INVALID_HANDLE_VALUE) {
CloseHandle(file_handle);
}
Py_END_ALLOW_THREADS
#endif /* MS_WINDOWS */

#ifdef UNIX
if (0 <= self->fd)
(void) close(self->fd);
int fd = self->fd;
char *data = self->data;
self->fd = -1;
if (self->data != NULL) {
munmap(self->data, self->size);
self->data = NULL;
self->data = NULL;
Py_BEGIN_ALLOW_THREADS
if (0 <= fd)
(void) close(fd);
if (data != NULL) {
munmap(data, self->size);
}
Py_END_ALLOW_THREADS
#endif

Py_RETURN_NONE;
Expand Down