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author | Benjamin Peterson <benjamin@python.org> | 2014-06-16 19:39:18 -0700 |
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committer | Benjamin Peterson <benjamin@python.org> | 2014-06-16 19:39:18 -0700 |
commit | 821ae956ccb2d1ef5b16a7e056afb3b1b3df19e7 (patch) | |
tree | 70ff1f8b7b63e5a07584e0fd8deb917017073dc7 | |
parent | 80db9e42e6eb7b2de89bca454c253cbfe509b748 (diff) | |
download | cpython-821ae956ccb2d1ef5b16a7e056afb3b1b3df19e7.tar.gz |
avoid crashes and lockups from daemon threads during interpreter shutdown (#1856)
-rw-r--r-- | Include/pythonrun.h | 2 | ||||
-rw-r--r-- | Lib/test/test_threading.py | 43 | ||||
-rw-r--r-- | Misc/NEWS | 4 | ||||
-rw-r--r-- | Python/ceval.c | 6 | ||||
-rw-r--r-- | Python/pythonrun.c | 9 | ||||
-rw-r--r-- | Python/thread_pthread.h | 4 |
6 files changed, 65 insertions, 3 deletions
diff --git a/Include/pythonrun.h b/Include/pythonrun.h index 6bfc175050..c319c520d4 100644 --- a/Include/pythonrun.h +++ b/Include/pythonrun.h @@ -146,6 +146,8 @@ PyAPI_FUNC(void) PyFloat_Fini(void); PyAPI_FUNC(void) PyOS_FiniInterrupts(void); PyAPI_FUNC(void) PyByteArray_Fini(void); +PyAPI_DATA(PyThreadState *) _Py_Finalizing; + /* Stuff with no proper home (yet) */ PyAPI_FUNC(char *) PyOS_Readline(FILE *, FILE *, char *); PyAPI_DATA(int) (*PyOS_InputHook)(void); diff --git a/Lib/test/test_threading.py b/Lib/test/test_threading.py index 1653d36205..86c953f4d6 100644 --- a/Lib/test/test_threading.py +++ b/Lib/test/test_threading.py @@ -700,6 +700,49 @@ class ThreadJoinOnShutdown(BaseTestCase): output = "end of worker thread\nend of main thread\n" self.assertScriptHasOutput(script, output) + @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") + def test_6_daemon_threads(self): + # Check that a daemon thread cannot crash the interpreter on shutdown + # by manipulating internal structures that are being disposed of in + # the main thread. + script = """if True: + import os + import random + import sys + import time + import threading + + thread_has_run = set() + + def random_io(): + '''Loop for a while sleeping random tiny amounts and doing some I/O.''' + while True: + in_f = open(os.__file__, 'rb') + stuff = in_f.read(200) + null_f = open(os.devnull, 'wb') + null_f.write(stuff) + time.sleep(random.random() / 1995) + null_f.close() + in_f.close() + thread_has_run.add(threading.current_thread()) + + def main(): + count = 0 + for _ in range(40): + new_thread = threading.Thread(target=random_io) + new_thread.daemon = True + new_thread.start() + count += 1 + while len(thread_has_run) < count: + time.sleep(0.001) + # Trigger process shutdown + sys.exit(0) + + main() + """ + rc, out, err = assert_python_ok('-c', script) + self.assertFalse(err) + @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") @unittest.skipIf(sys.platform in platforms_to_skip, "due to known OS bug") def test_reinit_tls_after_fork(self): @@ -10,6 +10,10 @@ What's New in Python 2.7.8? Core and Builtins ----------------- +- Issue #1856: Avoid crashes and lockups when daemon threads run while the + interpreter is shutting down; instead, these threads are now killed when they + try to take the GIL. + - Issue #19656: Running Python with the -3 option now also warns about non-ascii bytes literals. diff --git a/Python/ceval.c b/Python/ceval.c index 18bc66b871..b1f5e8eedb 100644 --- a/Python/ceval.c +++ b/Python/ceval.c @@ -355,6 +355,12 @@ PyEval_RestoreThread(PyThreadState *tstate) if (interpreter_lock) { int err = errno; PyThread_acquire_lock(interpreter_lock, 1); + /* _Py_Finalizing is protected by the GIL */ + if (_Py_Finalizing && tstate != _Py_Finalizing) { + PyThread_release_lock(interpreter_lock); + PyThread_exit_thread(); + assert(0); /* unreachable */ + } errno = err; } #endif diff --git a/Python/pythonrun.c b/Python/pythonrun.c index 2a40c0b570..748a63b955 100644 --- a/Python/pythonrun.c +++ b/Python/pythonrun.c @@ -91,6 +91,8 @@ int _Py_QnewFlag = 0; int Py_NoUserSiteDirectory = 0; /* for -s and site.py */ int Py_HashRandomizationFlag = 0; /* for -R and PYTHONHASHSEED */ +PyThreadState *_Py_Finalizing = NULL; + /* Hack to force loading of object files */ int (*_PyOS_mystrnicmp_hack)(const char *, const char *, Py_ssize_t) = \ @@ -163,6 +165,7 @@ Py_InitializeEx(int install_sigs) if (initialized) return; initialized = 1; + _Py_Finalizing = NULL; if ((p = Py_GETENV("PYTHONDEBUG")) && *p != '\0') Py_DebugFlag = add_flag(Py_DebugFlag, p); @@ -422,12 +425,16 @@ Py_Finalize(void) * the threads created via Threading. */ call_sys_exitfunc(); - initialized = 0; /* Get current thread state and interpreter pointer */ tstate = PyThreadState_GET(); interp = tstate->interp; + /* Remaining threads (e.g. daemon threads) will automatically exit + after taking the GIL (in PyEval_RestoreThread()). */ + _Py_Finalizing = tstate; + initialized = 0; + /* Disable signal handling */ PyOS_FiniInterrupts(); diff --git a/Python/thread_pthread.h b/Python/thread_pthread.h index c9ed796cd0..0c1fdfea2a 100644 --- a/Python/thread_pthread.h +++ b/Python/thread_pthread.h @@ -242,9 +242,9 @@ void PyThread_exit_thread(void) { dprintf(("PyThread_exit_thread called\n")); - if (!initialized) { + if (!initialized) exit(0); - } + pthread_exit(0); } #ifdef USE_SEMAPHORES |