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gh-120837: Update _Py_DumpExtensionModules to be async-signal-safe (gh-121051)

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Donghee Na 2024-06-28 06:46:46 +09:00 committed by GitHub
parent 237baf4d7a
commit 1a2e7a7475
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1 changed files with 36 additions and 2 deletions
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38
Python/pylifecycle.c
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@ -3035,6 +3035,30 @@ fatal_error_exit(int status)
}
}
static inline int
acquire_dict_lock_for_dump(PyObject *obj)
{
#ifdef Py_GIL_DISABLED
PyMutex *mutex = &obj->ob_mutex;
if (_PyMutex_LockTimed(mutex, 0, 0) == PY_LOCK_ACQUIRED) {
return 1;
}
return 0;
#else
return 1;
#endif
}
static inline void
release_dict_lock_for_dump(PyObject *obj)
{
#ifdef Py_GIL_DISABLED
PyMutex *mutex = &obj->ob_mutex;
// We can not call PyMutex_Unlock because it's not async-signal-safe.
// So not to wake up other threads, we just use a simple atomic store in here.
_Py_atomic_store_uint8(&mutex->_bits, _Py_UNLOCKED);
#endif
}
// Dump the list of extension modules of sys.modules, excluding stdlib modules
// (sys.stdlib_module_names), into fd file descriptor.
@ -3062,13 +3086,18 @@ _Py_DumpExtensionModules(int fd, PyInterpreterState *interp)
PyObject *stdlib_module_names = NULL;
if (interp->sysdict != NULL) {
pos = 0;
while (PyDict_Next(interp->sysdict, &pos, &key, &value)) {
if (!acquire_dict_lock_for_dump(interp->sysdict)) {
// If we cannot acquire the lock, just don't dump the list of extension modules.
return;
}
while (_PyDict_Next(interp->sysdict, &pos, &key, &value, NULL)) {
if (PyUnicode_Check(key)
&& PyUnicode_CompareWithASCIIString(key, "stdlib_module_names") == 0) {
stdlib_module_names = value;
break;
}
}
release_dict_lock_for_dump(interp->sysdict);
}
// If we failed to get sys.stdlib_module_names or it's not a frozenset,
// don't exclude stdlib modules.
@ -3080,7 +3109,11 @@ _Py_DumpExtensionModules(int fd, PyInterpreterState *interp)
int header = 1;
Py_ssize_t count = 0;
pos = 0;
while (PyDict_Next(modules, &pos, &key, &value)) {
if (!acquire_dict_lock_for_dump(modules)) {
// If we cannot acquire the lock, just don't dump the list of extension modules.
return;
}
while (_PyDict_Next(modules, &pos, &key, &value, NULL)) {
if (!PyUnicode_Check(key)) {
continue;
}
@ -3121,6 +3154,7 @@ _Py_DumpExtensionModules(int fd, PyInterpreterState *interp)
_Py_DumpASCII(fd, key);
count++;
}
release_dict_lock_for_dump(modules);
if (count) {
PUTS(fd, " (total: ");