cpython: 2a19d09b08f8 (original) (raw)

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changeset 69832:2a19d09b08f8 3.2

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. [#1856]

Antoine Pitrou solipsis@pitrou.net
date	Wed, 04 May 2011 20:02:30 +0200
parents	cc7342b4e59d
children	c892b0321d23 52fb7dc721ed
files	Include/pythonrun.h Lib/test/test_threading.py Misc/NEWS Python/ceval.c Python/pythonrun.c Python/thread_pthread.h
diffstat	6 files changed, 69 insertions(+), 7 deletions(-)[+] [-] Include/pythonrun.h 2 Lib/test/test_threading.py 45 Misc/NEWS 4 Python/ceval.c 6 Python/pythonrun.c 15 Python/thread_pthread.h 4

line wrap: on

line diff

--- a/Include/pythonrun.h +++ b/Include/pythonrun.h @@ -214,6 +214,8 @@ PyAPI_FUNC(void) PyByteArray_Fini(void); PyAPI_FUNC(void) PyFloat_Fini(void); PyAPI_FUNC(void) PyOS_FiniInterrupts(void); PyAPI_FUNC(void) _PyGC_Fini(void); + +PyAPI_DATA(PyThreadState ) _Py_Finalizing; #endif / Stuff with no proper home (yet) */

--- a/Lib/test/test_threading.py +++ b/Lib/test/test_threading.py @@ -12,6 +12,7 @@ import unittest import weakref import os import subprocess +from test.script_helper import assert_python_ok from test import lock_tests @@ -463,7 +464,6 @@ class ThreadJoinOnShutdown(BaseTestCase) """ self._run_and_join(script) - @unittest.skipUnless(hasattr(os, 'fork'), "needs os.fork()") def test_2_join_in_forked_process(self): # Like the test above, but from a forked interpreter @@ -655,6 +655,49 @@ class ThreadJoinOnShutdown(BaseTestCase) output = "end of worker thread\nend of main thread\n" self.assertScriptHasOutput(script, output)

def test_6_daemon_threads(self):

   # Check that a daemon thread cannot crash the interpreter on shutdown[](#l2.24)

   # by manipulating internal structures that are being disposed of in[](#l2.25)

```
   # the main thread.[](#l2.26)
```
```
   script = """if True:[](#l2.27)
```
```
       import os[](#l2.28)
```
```
       import random[](#l2.29)
```
```
       import sys[](#l2.30)
```
```
       import time[](#l2.31)
```
```
       import threading[](#l2.32)
```

```
       thread_has_run = set()[](#l2.34)
```

```
       def random_io():[](#l2.36)
```

           '''Loop for a while sleeping random tiny amounts and doing some I/O.'''[](#l2.37)

```
           blank = b'x' * 200[](#l2.38)
```
```
           while True:[](#l2.39)
```

               in_f = open(os.__file__, 'r')[](#l2.40)

               stuff = in_f.read(200)[](#l2.41)

               null_f = open(os.devnull, 'w')[](#l2.42)

               null_f.write(stuff)[](#l2.43)

               time.sleep(random.random() / 1995)[](#l2.44)

```
               null_f.close()[](#l2.45)
```
```
               in_f.close()[](#l2.46)
```

               thread_has_run.add(threading.current_thread())[](#l2.47)

```
       def main():[](#l2.49)
```
```
           count = 0[](#l2.50)
```

           for _ in range(40):[](#l2.51)

               new_thread = threading.Thread(target=random_io)[](#l2.52)

               new_thread.daemon = True[](#l2.53)

               new_thread.start()[](#l2.54)

```
               count += 1[](#l2.55)
```

           while len(thread_has_run) < count:[](#l2.56)

               time.sleep(0.001)[](#l2.57)

           # Trigger process shutdown[](#l2.58)

```
           sys.exit(0)[](#l2.59)
```

```
       main()[](#l2.61)
```
```
       """[](#l2.62)
```

   rc, out, err = assert_python_ok('-c', script)[](#l2.63)

```
   self.assertFalse(err)[](#l2.64)
```

+ class ThreadingExceptionTests(BaseTestCase): # A RuntimeError should be raised if Thread.start() is called

--- a/Misc/NEWS +++ b/Misc/NEWS @@ -10,6 +10,10 @@ What's New in Python 3.2.1? 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 #9756: When calling a method descriptor or a slot wrapper descriptor, the check of the object type doesn't read the class attribute anymore. Fix a crash if a class override its class attribute (e.g. a proxy of the

--- a/Python/ceval.c +++ b/Python/ceval.c @@ -440,6 +440,12 @@ PyEval_RestoreThread(PyThreadState *tsta if (gil_created()) { int err = errno; take_gil(tstate);

   /* _Py_Finalizing is protected by the GIL */[](#l4.7)

   if (_Py_Finalizing && tstate != _Py_Finalizing) {[](#l4.8)

```
       drop_gil(tstate);[](#l4.9)
```

       PyThread_exit_thread();[](#l4.10)

       assert(0);  /* unreachable */[](#l4.11)

   }[](#l4.12)
   errno = err;[](#l4.13)

}

#endif

--- a/Python/pythonrun.c +++ b/Python/pythonrun.c @@ -90,6 +90,8 @@ int Py_IgnoreEnvironmentFlag; /* e.g. PY int Py_NoUserSiteDirectory = 0; /* for -s and site.py / int Py_UnbufferedStdioFlag = 0; / Unbuffered binary std{in,out,err} */ +PyThreadState _Py_Finalizing = NULL; + / PyModule_GetWarningsModule is no longer necessary as of 2.6 since _warnings is builtin. This API should not be used. */ PyObject * @@ -188,6 +190,7 @@ Py_InitializeEx(int install_sigs) if (initialized) return; initialized = 1;

_Py_Finalizing = NULL;

#if defined(HAVE_LANGINFO_H) && defined(HAVE_SETLOCALE) /* Set up the LC_CTYPE locale, so we can obtain @@ -388,15 +391,19 @@ Py_Finalize(void) * the threads created via Threading. */ call_py_exitfuncs(); +

/* 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()). */[](#l5.30)

_Py_Finalizing = tstate; initialized = 0; /* Flush stdout+stderr */ flush_std_files();

/* Get current thread state and interpreter pointer */
tstate = PyThreadState_GET();
interp = tstate->interp;

- /* Disable signal handling */ PyOS_FiniInterrupts();

--- a/Python/thread_pthread.h +++ b/Python/thread_pthread.h @@ -250,9 +250,9 @@ void PyThread_exit_thread(void) { dprintf(("PyThread_exit_thread called\n"));

if (!initialized) {

if (!initialized) exit(0);

}

pthread_exit(0);

} #ifdef USE_SEMAPHORES