bpo-33608: Make sure locks in the runtime are properly re-created. (gh-12245)

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Eric Snow 2019-03-08 23:44:33 -07:00 committed by GitHub
parent 5be45a6105
commit 8479a3426e
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GPG Key ID: 4AEE18F83AFDEB23
4 changed files with 40 additions and 40 deletions

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@ -229,6 +229,7 @@ typedef struct pyruntimestate {
PyAPI_DATA(_PyRuntimeState) _PyRuntime;
PyAPI_FUNC(_PyInitError) _PyRuntimeState_Init(_PyRuntimeState *);
PyAPI_FUNC(void) _PyRuntimeState_Fini(_PyRuntimeState *);
PyAPI_FUNC(void) _PyRuntimeState_ReInitThreads(void);
/* Initialize _PyRuntimeState.
Return NULL on success, or return an error message on failure. */

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@ -429,6 +429,7 @@ PyOS_AfterFork_Child(void)
PyEval_ReInitThreads();
_PyImport_ReInitLock();
_PySignal_AfterFork();
_PyRuntimeState_ReInitThreads();
run_at_forkers(_PyInterpreterState_Get()->after_forkers_child, 0);
}

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@ -174,10 +174,10 @@ PyEval_InitThreads(void)
PyThread_init_thread();
create_gil();
take_gil(_PyThreadState_GET());
// Set it to the ID of the main thread of the main interpreter.
_PyRuntime.main_thread = PyThread_get_thread_ident();
if (!_PyRuntime.ceval.pending.lock) {
_PyRuntime.ceval.pending.lock = PyThread_allocate_lock();
_PyRuntime.ceval.pending.lock = PyThread_allocate_lock();
if (_PyRuntime.ceval.pending.lock == NULL) {
return Py_FatalError("Can't initialize threads for pending calls");
}
}
@ -246,8 +246,11 @@ PyEval_ReInitThreads(void)
return;
recreate_gil();
take_gil(current_tstate);
_PyRuntime.main_thread = PyThread_get_thread_ident();
_PyRuntime.ceval.pending.lock = PyThread_allocate_lock();
if (_PyRuntime.ceval.pending.lock == NULL) {
Py_FatalError("Can't initialize threads for pending calls");
}
/* Destroy all threads except the current one */
_PyThreadState_DeleteExcept(current_tstate);
@ -362,35 +365,12 @@ _pop_pending_call(int (**func)(void *), void **arg)
int
Py_AddPendingCall(int (*func)(void *), void *arg)
{
PyThread_type_lock lock = _PyRuntime.ceval.pending.lock;
/* try a few times for the lock. Since this mechanism is used
* for signal handling (on the main thread), there is a (slim)
* chance that a signal is delivered on the same thread while we
* hold the lock during the Py_MakePendingCalls() function.
* This avoids a deadlock in that case.
* Note that signals can be delivered on any thread. In particular,
* on Windows, a SIGINT is delivered on a system-created worker
* thread.
* We also check for lock being NULL, in the unlikely case that
* this function is called before any bytecode evaluation takes place.
*/
if (lock != NULL) {
int i;
for (i = 0; i<100; i++) {
if (PyThread_acquire_lock(lock, NOWAIT_LOCK))
break;
}
if (i == 100)
return -1;
}
PyThread_acquire_lock(_PyRuntime.ceval.pending.lock, WAIT_LOCK);
int result = _push_pending_call(func, arg);
PyThread_release_lock(_PyRuntime.ceval.pending.lock);
/* signal main loop */
SIGNAL_PENDING_CALLS();
if (lock != NULL)
PyThread_release_lock(lock);
return result;
}
@ -439,15 +419,6 @@ make_pending_calls(void)
UNSIGNAL_PENDING_CALLS();
int res = 0;
if (!_PyRuntime.ceval.pending.lock) {
/* initial allocation of the lock */
_PyRuntime.ceval.pending.lock = PyThread_allocate_lock();
if (_PyRuntime.ceval.pending.lock == NULL) {
res = -1;
goto error;
}
}
/* perform a bounded number of calls, in case of recursion */
for (int i=0; i<NPENDINGCALLS; i++) {
int (*func)(void *) = NULL;

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@ -60,7 +60,8 @@ _PyRuntimeState_Init_impl(_PyRuntimeState *runtime)
return _Py_INIT_ERR("Can't initialize threads for cross-interpreter data registry");
}
// runtime->main_thread is set in PyEval_InitThreads().
// Set it to the ID of the main thread of the main interpreter.
runtime->main_thread = PyThread_get_thread_ident();
return _Py_INIT_OK();
}
@ -94,6 +95,32 @@ _PyRuntimeState_Fini(_PyRuntimeState *runtime)
PyMem_SetAllocator(PYMEM_DOMAIN_RAW, &old_alloc);
}
/* This function is called from PyOS_AfterFork_Child to ensure that
* newly created child processes do not share locks with the parent.
*/
void
_PyRuntimeState_ReInitThreads(void)
{
// This was initially set in _PyRuntimeState_Init().
_PyRuntime.main_thread = PyThread_get_thread_ident();
_PyRuntime.interpreters.mutex = PyThread_allocate_lock();
if (_PyRuntime.interpreters.mutex == NULL) {
Py_FatalError("Can't initialize lock for runtime interpreters");
}
_PyRuntime.interpreters.main->id_mutex = PyThread_allocate_lock();
if (_PyRuntime.interpreters.main->id_mutex == NULL) {
Py_FatalError("Can't initialize ID lock for main interpreter");
}
_PyRuntime.xidregistry.mutex = PyThread_allocate_lock();
if (_PyRuntime.xidregistry.mutex == NULL) {
Py_FatalError("Can't initialize lock for cross-interpreter data registry");
}
}
#define HEAD_LOCK() PyThread_acquire_lock(_PyRuntime.interpreters.mutex, \
WAIT_LOCK)
#define HEAD_UNLOCK() PyThread_release_lock(_PyRuntime.interpreters.mutex)