https://github.com/python/cpython/commit/192c54713b4c67a8d14b2d98056771feba4... commit: 192c54713b4c67a8d14b2d98056771feba40ca37 branch: 3.7 author: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> committer: GitHub <noreply@github.com> date: 2018-10-31T16:45:42-07:00 summary: bpo-26558: Fix Py_FatalError() with GIL released (GH-10267) Don't call _Py_FatalError_PrintExc() nor flush_std_files() if the current thread doesn't hold the GIL, or if the current thread has no Python state thread. (cherry picked from commit 3a228ab17c2a9cffd1a2f15f30d6209768de20a6) Co-authored-by: Victor Stinner <vstinner@redhat.com> files: M Python/pylifecycle.c diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c index c01b21ffebad..86f95de8336f 100644 --- a/Python/pylifecycle.c +++ b/Python/pylifecycle.c @@ -2015,12 +2015,6 @@ _Py_FatalError_PrintExc(int fd) PyObject *exception, *v, *tb; int has_tb; - if (PyThreadState_GET() == NULL) { - /* The GIL is released: trying to acquire it is likely to deadlock, - just give up. */ - return 0; - } - PyErr_Fetch(&exception, &v, &tb); if (exception == NULL) { /* No current exception */ @@ -2125,9 +2119,30 @@ fatal_error(const char *prefix, const char *msg, int status) fputs("\n", stderr); fflush(stderr); /* it helps in Windows debug build */ - /* Print the exception (if an exception is set) with its traceback, - * or display the current Python stack. */ - if (!_Py_FatalError_PrintExc(fd)) { + /* Check if the current thread has a Python thread state + and holds the GIL */ + PyThreadState *tss_tstate = PyGILState_GetThisThreadState(); + if (tss_tstate != NULL) { + PyThreadState *tstate = PyThreadState_GET(); + if (tss_tstate != tstate) { + /* The Python thread does not hold the GIL */ + tss_tstate = NULL; + } + } + else { + /* Py_FatalError() has been called from a C thread + which has no Python thread state. */ + } + int has_tstate_and_gil = (tss_tstate != NULL); + + if (has_tstate_and_gil) { + /* If an exception is set, print the exception with its traceback */ + if (!_Py_FatalError_PrintExc(fd)) { + /* No exception is set, or an exception is set without traceback */ + _Py_FatalError_DumpTracebacks(fd); + } + } + else { _Py_FatalError_DumpTracebacks(fd); } @@ -2138,7 +2153,7 @@ fatal_error(const char *prefix, const char *msg, int status) _PyFaulthandler_Fini(); /* Check if the current Python thread hold the GIL */ - if (PyThreadState_GET() != NULL) { + if (has_tstate_and_gil) { /* Flush sys.stdout and sys.stderr */ flush_std_files(); }