Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitce558e6

Browse files
chgnrdvblurb-it[bot]gpshead
authored
gh-104690 Disallow thread creation and fork at interpreter finalization (#104826)
Disallow thread creation and fork at interpreter finalization.in the following functions, check if interpreter is finalizing and raise `RuntimeError` with appropriate message:* `_thread.start_new_thread` and thus `threading`* `posix.fork`* `posix.fork1`* `posix.forkpty`* `_posixsubprocess.fork_exec` when a `preexec_fn=` is supplied.---------Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>Co-authored-by: Gregory P. Smith <greg@krypto.org>
1 parenteaff9c3 commitce558e6

File tree

8 files changed

+97
-30
lines changed

8 files changed

+97
-30
lines changed

‎Doc/library/atexit.rst

Lines changed: 10 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -48,6 +48,16 @@ a cleanup function is undefined.
4848
This function returns *func*, which makes it possible to use it as a
4949
decorator.
5050

51+
..warning::
52+
Starting new threads or calling:func:`os.fork` from a registered
53+
function can lead to race condition between the main Python
54+
runtime thread freeing thread states while internal:mod:`threading`
55+
routines or the new process try to use that state. This can lead to
56+
crashes rather than clean shutdown.
57+
58+
..versionchanged::3.12
59+
Attempts to start a new thread or:func:`os.fork` a new process
60+
in a registered function now leads to:exc:`RuntimeError`.
5161

5262
..function::unregister(func)
5363

‎Lib/test/test_os.py

Lines changed: 16 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -4706,6 +4706,22 @@ def test_fork_warns_when_non_python_thread_exists(self):
47064706
self.assertEqual(err.decode("utf-8"),"")
47074707
self.assertEqual(out.decode("utf-8"),"")
47084708

4709+
deftest_fork_at_exit(self):
4710+
code="""if 1:
4711+
import atexit
4712+
import os
4713+
4714+
def exit_handler():
4715+
pid = os.fork()
4716+
if pid != 0:
4717+
print("shouldn't be printed")
4718+
4719+
atexit.register(exit_handler)
4720+
"""
4721+
_,out,err=assert_python_ok("-c",code)
4722+
self.assertEqual(b"",out)
4723+
self.assertIn(b"can't fork at interpreter shutdown",err)
4724+
47094725

47104726
# Only test if the C version is provided, otherwise TestPEP519 already tested
47114727
# the pure Python implementation.

‎Lib/test/test_subprocess.py

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,6 +5,7 @@
55
fromtest.supportimportimport_helper
66
fromtest.supportimportos_helper
77
fromtest.supportimportwarnings_helper
8+
fromtest.support.script_helperimportassert_python_ok
89
importsubprocess
910
importsys
1011
importsignal
@@ -3329,6 +3330,24 @@ def test_communicate_repeated_call_after_stdout_close(self):
33293330
exceptsubprocess.TimeoutExpired:
33303331
pass
33313332

3333+
deftest_preexec_at_exit(self):
3334+
code=f"""if 1:
3335+
import atexit
3336+
import subprocess
3337+
3338+
def dummy():
3339+
pass
3340+
3341+
def exit_handler():
3342+
subprocess.Popen({ZERO_RETURN_CMD}, preexec_fn=dummy)
3343+
print("shouldn't be printed")
3344+
3345+
atexit.register(exit_handler)
3346+
"""
3347+
_,out,err=assert_python_ok("-c",code)
3348+
self.assertEqual(out,b'')
3349+
self.assertIn(b"preexec_fn not supported at interpreter shutdown",err)
3350+
33323351

33333352
@unittest.skipUnless(mswindows,"Windows specific tests")
33343353
classWin32ProcessTestCase(BaseTestCase):

‎Lib/test/test_threading.py

Lines changed: 16 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -531,34 +531,6 @@ def test_daemon_param(self):
531531
t=threading.Thread(daemon=True)
532532
self.assertTrue(t.daemon)
533533

534-
@support.requires_fork()
535-
deftest_fork_at_exit(self):
536-
# bpo-42350: Calling os.fork() after threading._shutdown() must
537-
# not log an error.
538-
code=textwrap.dedent("""
539-
import atexit
540-
import os
541-
import sys
542-
from test.support import wait_process
543-
544-
# Import the threading module to register its "at fork" callback
545-
import threading
546-
547-
def exit_handler():
548-
pid = os.fork()
549-
if not pid:
550-
print("child process ok", file=sys.stderr, flush=True)
551-
# child process
552-
else:
553-
wait_process(pid, exitcode=0)
554-
555-
# exit_handler() will be called after threading._shutdown()
556-
atexit.register(exit_handler)
557-
""")
558-
_,out,err=assert_python_ok("-c",code)
559-
self.assertEqual(out,b'')
560-
self.assertEqual(err.rstrip(),b'child process ok')
561-
562534
@support.requires_fork()
563535
deftest_dummy_thread_after_fork(self):
564536
# Issue #14308: a dummy thread in the active list doesn't mess up
@@ -1048,6 +1020,22 @@ def import_threading():
10481020
self.assertEqual(out,b'')
10491021
self.assertEqual(err,b'')
10501022

1023+
deftest_start_new_thread_at_exit(self):
1024+
code="""if 1:
1025+
import atexit
1026+
import _thread
1027+
1028+
def f():
1029+
print("shouldn't be printed")
1030+
1031+
def exit_handler():
1032+
_thread.start_new_thread(f, ())
1033+
1034+
atexit.register(exit_handler)
1035+
"""
1036+
_,out,err=assert_python_ok("-c",code)
1037+
self.assertEqual(out,b'')
1038+
self.assertIn(b"can't create new thread at interpreter shutdown",err)
10511039

10521040
classThreadJoinOnShutdown(BaseTestCase):
10531041

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,6 @@
1+
Starting new threads and process creation through:func:`os.fork` during interpreter
2+
shutdown (such as from:mod:`atexit` handlers) is no longer supported. It can lead
3+
to race condition between the main Python runtime thread freeing thread states while
4+
internal:mod:`threading` routines are trying to allocate and use the state of just
5+
created threads. Or forked children trying to use the mid-shutdown runtime and thread
6+
state in the child process.

‎Modules/_posixsubprocess.c

Lines changed: 6 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -5,6 +5,7 @@
55

66
#include"Python.h"
77
#include"pycore_fileutils.h"
8+
#include"pycore_pystate.h"
89
#if defined(HAVE_PIPE2)&& !defined(_GNU_SOURCE)
910
# define_GNU_SOURCE
1011
#endif
@@ -943,6 +944,11 @@ subprocess_fork_exec_impl(PyObject *module, PyObject *process_args,
943944
Py_ssize_tfds_to_keep_len=PyTuple_GET_SIZE(py_fds_to_keep);
944945

945946
PyInterpreterState*interp=PyInterpreterState_Get();
947+
if ((preexec_fn!=Py_None)&&interp->finalizing) {
948+
PyErr_SetString(PyExc_RuntimeError,
949+
"preexec_fn not supported at interpreter shutdown");
950+
returnNULL;
951+
}
946952
if ((preexec_fn!=Py_None)&& (interp!=PyInterpreterState_Main())) {
947953
PyErr_SetString(PyExc_RuntimeError,
948954
"preexec_fn not supported within subinterpreters");

‎Modules/_threadmodule.c

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1155,6 +1155,11 @@ thread_PyThread_start_new_thread(PyObject *self, PyObject *fargs)
11551155
"thread is not supported for isolated subinterpreters");
11561156
returnNULL;
11571157
}
1158+
if (interp->finalizing) {
1159+
PyErr_SetString(PyExc_RuntimeError,
1160+
"can't create new thread at interpreter shutdown");
1161+
returnNULL;
1162+
}
11581163

11591164
structbootstate*boot=PyMem_NEW(structbootstate,1);
11601165
if (boot==NULL) {

‎Modules/posixmodule.c

Lines changed: 19 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -7620,7 +7620,13 @@ os_fork1_impl(PyObject *module)
76207620
{
76217621
pid_tpid;
76227622

7623-
if (!_Py_IsMainInterpreter(_PyInterpreterState_GET())) {
7623+
PyInterpreterState*interp=_PyInterpreterState_GET();
7624+
if (interp->finalizing) {
7625+
PyErr_SetString(PyExc_RuntimeError,
7626+
"can't fork at interpreter shutdown");
7627+
returnNULL;
7628+
}
7629+
if (!_Py_IsMainInterpreter(interp)) {
76247630
PyErr_SetString(PyExc_RuntimeError,"fork not supported for subinterpreters");
76257631
returnNULL;
76267632
}
@@ -7656,6 +7662,11 @@ os_fork_impl(PyObject *module)
76567662
{
76577663
pid_tpid;
76587664
PyInterpreterState*interp=_PyInterpreterState_GET();
7665+
if (interp->finalizing) {
7666+
PyErr_SetString(PyExc_RuntimeError,
7667+
"can't fork at interpreter shutdown");
7668+
returnNULL;
7669+
}
76597670
if (!_PyInterpreterState_HasFeature(interp,Py_RTFLAGS_FORK)) {
76607671
PyErr_SetString(PyExc_RuntimeError,
76617672
"fork not supported for isolated subinterpreters");
@@ -8327,7 +8338,13 @@ os_forkpty_impl(PyObject *module)
83278338
intmaster_fd=-1;
83288339
pid_tpid;
83298340

8330-
if (!_Py_IsMainInterpreter(_PyInterpreterState_GET())) {
8341+
PyInterpreterState*interp=_PyInterpreterState_GET();
8342+
if (interp->finalizing) {
8343+
PyErr_SetString(PyExc_RuntimeError,
8344+
"can't fork at interpreter shutdown");
8345+
returnNULL;
8346+
}
8347+
if (!_Py_IsMainInterpreter(interp)) {
83318348
PyErr_SetString(PyExc_RuntimeError,"fork not supported for subinterpreters");
83328349
returnNULL;
83338350
}

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp