diff --git a/Include/pystate.h b/Include/pystate.h index cf296959631..4919d99b6c7 100644 --- a/Include/pystate.h +++ b/Include/pystate.h @@ -21,6 +21,7 @@ typedef struct _is { PyObject *modules; PyObject *sysdict; PyObject *builtins; + PyObject *modules_reloading; PyObject *codec_search_path; PyObject *codec_search_cache; diff --git a/Lib/test/infinite_reload.py b/Lib/test/infinite_reload.py new file mode 100644 index 00000000000..bfbec91b0a1 --- /dev/null +++ b/Lib/test/infinite_reload.py @@ -0,0 +1,7 @@ +# For testing http://python.org/sf/742342, which reports that Python +# segfaults (infinite recursion in C) in the presence of infinite +# reload()ing. This module is imported by test_import.py:test_infinite_reload +# to make sure this doesn't happen any more. + +import infinite_reload +reload(infinite_reload) diff --git a/Lib/test/test_import.py b/Lib/test/test_import.py index a6db2812997..cc932a2ec2a 100644 --- a/Lib/test/test_import.py +++ b/Lib/test/test_import.py @@ -192,6 +192,16 @@ class ImportTest(unittest.TestCase): remove_files(TESTFN) if TESTFN in sys.modules: del sys.modules[TESTFN] + + def test_infinite_reload(self): + # Bug #742342 reports that Python segfaults (infinite recursion in C) + # when faced with self-recursive reload()ing. + + sys.path.insert(0, os.path.dirname(__file__)) + try: + import infinite_reload + finally: + sys.path.pop(0) def test_import_name_binding(self): # import x.y.z binds x in the current namespace diff --git a/Misc/NEWS b/Misc/NEWS index 67f417a2b4e..0bd82c2debc 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -19,6 +19,9 @@ Core and builtins its argument, if it exists. If not, it will work like before. This allows customizing the output of dir() in the presence of a __getattr__(). +- Patch #922167: Python no longer segfaults when faced with infinitely + self-recursive reload() calls (as reported by bug #742342). + - Patch #1675981: remove unreachable code from ``type.__new__()`` method. - Patch #1491866: change the complex() constructor to allow parthensized diff --git a/Python/import.c b/Python/import.c index db39cc4ee0a..d7f012ac1c3 100644 --- a/Python/import.c +++ b/Python/import.c @@ -340,6 +340,25 @@ imp_release_lock(PyObject *self, PyObject *noargs) return Py_None; } +PyObject * +PyImport_GetModulesReloading(void) +{ + PyInterpreterState *interp = PyThreadState_Get()->interp; + if (interp->modules_reloading == NULL) + Py_FatalError("PyImport_GetModuleDict: no modules_reloading dictionary!"); + return interp->modules_reloading; +} + +static void +imp_modules_reloading_clear (void) +{ + PyInterpreterState *interp = PyThreadState_Get()->interp; + if (interp->modules_reloading == NULL) + return; + PyDict_Clear(interp->modules_reloading); + return; +} + /* Helper for sys */ PyObject * @@ -499,6 +518,7 @@ PyImport_Cleanup(void) PyDict_Clear(modules); interp->modules = NULL; Py_DECREF(modules); + Py_CLEAR(interp->modules_reloading); } @@ -2401,8 +2421,9 @@ import_submodule(PyObject *mod, char *subname, char *fullname) PyObject * PyImport_ReloadModule(PyObject *m) { + PyObject *modules_reloading = PyImport_GetModulesReloading(); PyObject *modules = PyImport_GetModuleDict(); - PyObject *path = NULL, *loader = NULL; + PyObject *path = NULL, *loader = NULL, *existing_m = NULL; char *name, *subname; char buf[MAXPATHLEN+1]; struct filedescr *fdp; @@ -2423,20 +2444,30 @@ PyImport_ReloadModule(PyObject *m) name); return NULL; } + if ((existing_m = PyDict_GetItemString(modules_reloading, name)) != NULL) { + /* Due to a recursive reload, this module is already being reloaded. */ + Py_INCREF(existing_m); + return existing_m; + } + PyDict_SetItemString(modules_reloading, name, m); + subname = strrchr(name, '.'); if (subname == NULL) subname = name; else { PyObject *parentname, *parent; parentname = PyString_FromStringAndSize(name, (subname-name)); - if (parentname == NULL) + if (parentname == NULL) { + imp_modules_reloading_clear(); return NULL; + } parent = PyDict_GetItem(modules, parentname); if (parent == NULL) { PyErr_Format(PyExc_ImportError, "reload(): parent %.200s not in sys.modules", PyString_AS_STRING(parentname)); Py_DECREF(parentname); + imp_modules_reloading_clear(); return NULL; } Py_DECREF(parentname); @@ -2451,6 +2482,7 @@ PyImport_ReloadModule(PyObject *m) if (fdp == NULL) { Py_XDECREF(loader); + imp_modules_reloading_clear(); return NULL; } @@ -2467,6 +2499,7 @@ PyImport_ReloadModule(PyObject *m) */ PyDict_SetItemString(modules, name, m); } + imp_modules_reloading_clear (); return newm; } diff --git a/Python/pystate.c b/Python/pystate.c index cc25e3ed38e..086789d3553 100644 --- a/Python/pystate.c +++ b/Python/pystate.c @@ -68,6 +68,7 @@ PyInterpreterState_New(void) Py_FatalError("Can't initialize threads for interpreter"); #endif interp->modules = NULL; + interp->modules_reloading = NULL; interp->sysdict = NULL; interp->builtins = NULL; interp->tstate_head = NULL; @@ -107,6 +108,7 @@ PyInterpreterState_Clear(PyInterpreterState *interp) Py_CLEAR(interp->codec_search_cache); Py_CLEAR(interp->codec_error_registry); Py_CLEAR(interp->modules); + Py_CLEAR(interp->modules_reloading); Py_CLEAR(interp->sysdict); Py_CLEAR(interp->builtins); } diff --git a/Python/pythonrun.c b/Python/pythonrun.c index 3a9e75e2373..3e5ecfe3f62 100644 --- a/Python/pythonrun.c +++ b/Python/pythonrun.c @@ -194,6 +194,9 @@ Py_InitializeEx(int install_sigs) interp->modules = PyDict_New(); if (interp->modules == NULL) Py_FatalError("Py_Initialize: can't make modules dictionary"); + interp->modules_reloading = PyDict_New(); + if (interp->modules_reloading == NULL) + Py_FatalError("Py_Initialize: can't make modules_reloading dictionary"); #ifdef Py_USING_UNICODE /* Init Unicode implementation; relies on the codec registry */ @@ -531,6 +534,7 @@ Py_NewInterpreter(void) /* XXX The following is lax in error checking */ interp->modules = PyDict_New(); + interp->modules_reloading = PyDict_New(); bimod = _PyImport_FindExtension("__builtin__", "__builtin__"); if (bimod != NULL) {