python · zooba · Feb 2, 2019 · Jun 19, 2018
diff --git a/Misc/NEWS.d/next/Windows/2018-06-19-11-57-50.bpo-33895.zpblTy.rst b/Misc/NEWS.d/next/Windows/2018-06-19-11-57-50.bpo-33895.zpblTy.rst
@@ -0,0 +1 @@
+GIL is released while calling functions that acquire Windows loader lock.
diff --git a/Modules/_ctypes/_ctypes.c b/Modules/_ctypes/_ctypes.c
@@ -663,7 +663,9 @@ CDataType_in_dll(PyObject *type, PyObject *args)
     }
 
 #ifdef MS_WIN32
+    Py_BEGIN_ALLOW_THREADS
     address = (void *)GetProcAddress(handle, name);
+    Py_END_ALLOW_THREADS
     if (!address) {
         PyErr_Format(PyExc_ValueError,
                      "symbol '%s' not found",
@@ -3157,18 +3159,23 @@ static PyGetSetDef PyCFuncPtr_getsets[] = {
 #ifdef MS_WIN32
 static PPROC FindAddress(void *handle, const char *name, PyObject *type)
 {
+    PPROC address;
 #ifdef MS_WIN64
     /* win64 has no stdcall calling conv, so it should
        also not have the name mangling of it.
     */
-    return (PPROC)GetProcAddress(handle, name);
+    Py_BEGIN_ALLOW_THREADS
+    address = (PPROC)GetProcAddress(handle, name);
+    Py_END_ALLOW_THREADS
+    return address;
 #else
-    PPROC address;
     char *mangled_name;
     int i;
     StgDictObject *dict;
 
+    Py_BEGIN_ALLOW_THREADS
     address = (PPROC)GetProcAddress(handle, name);
+    Py_END_ALLOW_THREADS
     if (address)
         return address;
     if (((size_t)name & ~0xFFFF) == 0) {
@@ -3189,7 +3196,9 @@ static PPROC FindAddress(void *handle, const char *name, PyObject *type)
         return NULL;
     for (i = 0; i < 32; ++i) {
         sprintf(mangled_name, "_%s@%d", name, i*4);
+        Py_BEGIN_ALLOW_THREADS
         address = (PPROC)GetProcAddress(handle, mangled_name);
+        Py_END_ALLOW_THREADS
         if (address)
             return address;
     }

diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
@@ -1251,7 +1251,10 @@ static PyObject *load_library(PyObject *self, PyObject *args)
     if (!name)
         return NULL;
 
+    Py_BEGIN_ALLOW_THREADS
     hMod = LoadLibraryW(name);
+    Py_END_ALLOW_THREADS
+
     if (!hMod)
         return PyErr_SetFromWindowsErr(GetLastError());
 #ifdef _WIN64
@@ -1268,9 +1271,15 @@ Free the handle of an executable previously loaded by LoadLibrary.\n";
 static PyObject *free_library(PyObject *self, PyObject *args)
 {
     void *hMod;
+    BOOL result;
     if (!PyArg_ParseTuple(args, "O&:FreeLibrary", &_parse_voidp, &hMod))
         return NULL;
-    if (!FreeLibrary((HMODULE)hMod))
+
+    Py_BEGIN_ALLOW_THREADS
+    result = FreeLibrary((HMODULE)hMod);
+    Py_END_ALLOW_THREADS
+
+    if (!result)
         return PyErr_SetFromWindowsErr(GetLastError());
     Py_RETURN_NONE;
 }

diff --git a/Modules/overlapped.c b/Modules/overlapped.c
@@ -127,8 +127,10 @@ initialize_function_pointers(void)
     closesocket(s);
 
     /* On WinXP we will have Py_CancelIoEx == NULL */
+    Py_BEGIN_ALLOW_THREADS
     hKernel32 = GetModuleHandle("KERNEL32");
     *(FARPROC *)&Py_CancelIoEx = GetProcAddress(hKernel32, "CancelIoEx");
+    Py_END_ALLOW_THREADS
     return 0;
 }
 

diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
@@ -7534,9 +7534,13 @@ check_CreateSymbolicLink(void)
     /* only recheck */
     if (Py_CreateSymbolicLinkW)
         return 1;
+
+    Py_BEGIN_ALLOW_THREADS
     hKernel32 = GetModuleHandleW(L"KERNEL32");
     *(FARPROC*)&Py_CreateSymbolicLinkW = GetProcAddress(hKernel32,
                                                         "CreateSymbolicLinkW");
+    Py_END_ALLOW_THREADS
+
     return Py_CreateSymbolicLinkW != NULL;
 }
 
@@ -11049,14 +11053,14 @@ check_ShellExecute()
            the system SHELL32.DLL, even if there is another SHELL32.DLL
            in the DLL search path. */
         hShell32 = LoadLibraryW(L"SHELL32");
-        Py_END_ALLOW_THREADS
         if (hShell32) {
             *(FARPROC*)&Py_ShellExecuteW = GetProcAddress(hShell32,
                                             "ShellExecuteW");
             has_ShellExecute = Py_ShellExecuteW != NULL;
         } else {
             has_ShellExecute = 0;
         }
+        Py_END_ALLOW_THREADS
     }
     return has_ShellExecute;
 }
@@ -11669,11 +11673,12 @@ os_cpu_count_impl(PyObject *module)
     /* Vista is supported and the GetMaximumProcessorCount API is Win7+
        Need to fallback to Vista behavior if this call isn't present */
     HINSTANCE hKernel32;
-    hKernel32 = GetModuleHandleW(L"KERNEL32");
-
     static DWORD(CALLBACK *_GetMaximumProcessorCount)(WORD) = NULL;
+    Py_BEGIN_ALLOW_THREADS
+    hKernel32 = GetModuleHandleW(L"KERNEL32");
     *(FARPROC*)&_GetMaximumProcessorCount = GetProcAddress(hKernel32,
         "GetMaximumProcessorCount");
+    Py_END_ALLOW_THREADS
     if (_GetMaximumProcessorCount != NULL) {
         ncpu = _GetMaximumProcessorCount(ALL_PROCESSOR_GROUPS);
     }

diff --git a/PC/winreg.c b/PC/winreg.c
@@ -979,10 +979,12 @@ winreg_DeleteKeyEx_impl(PyObject *module, HKEY key, Py_UNICODE *sub_key,
 
     /* Only available on 64bit platforms, so we must load it
        dynamically. */
+    Py_BEGIN_ALLOW_THREADS
     hMod = GetModuleHandleW(L"advapi32.dll");
     if (hMod)
         pfn = (RDKEFunc)GetProcAddress(hMod,
                                                                    "RegDeleteKeyExW");
+    Py_END_ALLOW_THREADS
     if (!pfn) {
         PyErr_SetString(PyExc_NotImplementedError,
                                         "not implemented on this platform");
@@ -1707,10 +1709,12 @@ winreg_DisableReflectionKey_impl(PyObject *module, HKEY key)
 
     /* Only available on 64bit platforms, so we must load it
        dynamically.*/
+    Py_BEGIN_ALLOW_THREADS
     hMod = GetModuleHandleW(L"advapi32.dll");
     if (hMod)
         pfn = (RDRKFunc)GetProcAddress(hMod,
                                        "RegDisableReflectionKey");
+    Py_END_ALLOW_THREADS
     if (!pfn) {
         PyErr_SetString(PyExc_NotImplementedError,
                         "not implemented on this platform");
@@ -1750,10 +1754,12 @@ winreg_EnableReflectionKey_impl(PyObject *module, HKEY key)
 
     /* Only available on 64bit platforms, so we must load it
        dynamically.*/
+    Py_BEGIN_ALLOW_THREADS
     hMod = GetModuleHandleW(L"advapi32.dll");
     if (hMod)
         pfn = (RERKFunc)GetProcAddress(hMod,
                                        "RegEnableReflectionKey");
+    Py_END_ALLOW_THREADS
     if (!pfn) {
         PyErr_SetString(PyExc_NotImplementedError,
                         "not implemented on this platform");
@@ -1792,10 +1798,12 @@ winreg_QueryReflectionKey_impl(PyObject *module, HKEY key)
 
     /* Only available on 64bit platforms, so we must load it
        dynamically.*/
+    Py_BEGIN_ALLOW_THREADS
     hMod = GetModuleHandleW(L"advapi32.dll");
     if (hMod)
         pfn = (RQRKFunc)GetProcAddress(hMod,
                                        "RegQueryReflectionKey");
+    Py_END_ALLOW_THREADS
     if (!pfn) {
         PyErr_SetString(PyExc_NotImplementedError,
                         "not implemented on this platform");

diff --git a/Python/dynload_win.c b/Python/dynload_win.c
@@ -218,8 +218,10 @@ dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
         /* We use LoadLibraryEx so Windows looks for dependent DLLs
             in directory of pathname first. */
         /* XXX This call doesn't exist in Windows CE */
+        Py_BEGIN_ALLOW_THREADS
         hDLL = LoadLibraryExW(wpathname, NULL,
                               LOAD_WITH_ALTERED_SEARCH_PATH);
+        Py_END_ALLOW_THREADS
 #if HAVE_SXS
         _Py_DeactivateActCtx(cookie);
 #endif
@@ -298,11 +300,15 @@ dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
                              "Module use of %.150s conflicts "
                              "with this version of Python.",
                              import_python);
+                Py_BEGIN_ALLOW_THREADS
                 FreeLibrary(hDLL);
+                Py_END_ALLOW_THREADS
                 return NULL;
             }
         }
+        Py_BEGIN_ALLOW_THREADS
         p = GetProcAddress(hDLL, funcname);
+        Py_END_ALLOW_THREADS
     }
 
     return p;

diff --git a/Python/sysmodule.c b/Python/sysmodule.c
@@ -1085,7 +1085,9 @@ sys_getwindowsversion(PyObject *self)
     // We need to read the version info from a system file resource
     // to accurately identify the OS version. If we fail for any reason,
     // just return whatever GetVersion said.
+    Py_BEGIN_ALLOW_THREADS
     hKernel32 = GetModuleHandleW(L"kernel32.dll");
+    Py_END_ALLOW_THREADS
     if (hKernel32 && GetModuleFileNameW(hKernel32, kernel32_path, MAX_PATH) &&
         (verblock_size = GetFileVersionInfoSizeW(kernel32_path, NULL)) &&
         (verblock = PyMem_RawMalloc(verblock_size))) {
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1 @@
		GIL is released while calling functions that acquire Windows loader lock.