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gh-116818: Make sys.settrace, sys.setprofile, and monitoring thread-safe (#116775)

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Makes sys.settrace, sys.setprofile, and monitoring generally thread-safe.

Mostly uses a stop-the-world approach and synchronization around the code object's _co_instrumentation_version.  There may be a little bit of extra synchronization around the monitoring data that's required to be TSAN clean.
This commit is contained in:
Dino Viehland 2024-04-19 14:47:42 -07:00 • committed by GitHub
parent b45af00bad
commit 07525c9a85
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GPG key ID: B5690EEEBB952194
18 changed files with 530 additions and 63 deletions
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98
Python/legacy_tracing.c
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@ -16,6 +16,13 @@ typedef struct _PyLegacyEventHandler {
int event;
} _PyLegacyEventHandler;
#ifdef Py_GIL_DISABLED
#define LOCK_SETUP() PyMutex_Lock(&_PyRuntime.ceval.sys_trace_profile_mutex);
#define UNLOCK_SETUP() PyMutex_Unlock(&_PyRuntime.ceval.sys_trace_profile_mutex);
#else
#define LOCK_SETUP()
#define UNLOCK_SETUP()
#endif
/* The Py_tracefunc function expects the following arguments:
* obj: the trace object (PyObject *)
* frame: the current frame (PyFrameObject *)
@ -414,19 +421,10 @@ is_tstate_valid(PyThreadState *tstate)
}
#endif
int
_PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
static Py_ssize_t
setup_profile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg, PyObject **old_profileobj)
{
assert(is_tstate_valid(tstate));
/* The caller must hold the GIL */
assert(PyGILState_Check());
/* Call _PySys_Audit() in the context of the current thread state,
even if tstate is not the current thread state. */
PyThreadState *current_tstate = _PyThreadState_GET();
if (_PySys_Audit(current_tstate, "sys.setprofile", NULL) < 0) {
return -1;
}
*old_profileobj = NULL;
/* Setup PEP 669 monitoring callbacks and events. */
if (!tstate->interp->sys_profile_initialized) {
tstate->interp->sys_profile_initialized = true;
@ -469,14 +467,36 @@ _PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
int delta = (func != NULL) - (tstate->c_profilefunc != NULL);
tstate->c_profilefunc = func;
PyObject *old_profileobj = tstate->c_profileobj;
*old_profileobj = tstate->c_profileobj;
tstate->c_profileobj = Py_XNewRef(arg);
Py_XDECREF(old_profileobj);
tstate->interp->sys_profiling_threads += delta;
assert(tstate->interp->sys_profiling_threads >= 0);
return tstate->interp->sys_profiling_threads;
}
int
_PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
{
assert(is_tstate_valid(tstate));
/* The caller must hold the GIL */
assert(PyGILState_Check());
/* Call _PySys_Audit() in the context of the current thread state,
even if tstate is not the current thread state. */
PyThreadState *current_tstate = _PyThreadState_GET();
if (_PySys_Audit(current_tstate, "sys.setprofile", NULL) < 0) {
return -1;
}
// needs to be decref'd outside of the lock
PyObject *old_profileobj;
LOCK_SETUP();
Py_ssize_t profiling_threads = setup_profile(tstate, func, arg, &old_profileobj);
UNLOCK_SETUP();
Py_XDECREF(old_profileobj);
uint32_t events = 0;
if (tstate->interp->sys_profiling_threads) {
if (profiling_threads) {
events =
(1 << PY_MONITORING_EVENT_PY_START) | (1 << PY_MONITORING_EVENT_PY_RESUME) |
(1 << PY_MONITORING_EVENT_PY_RETURN) | (1 << PY_MONITORING_EVENT_PY_YIELD) |
@ -486,21 +506,10 @@ _PyEval_SetProfile(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
return _PyMonitoring_SetEvents(PY_MONITORING_SYS_PROFILE_ID, events);
}
int
_PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
static Py_ssize_t
setup_tracing(PyThreadState *tstate, Py_tracefunc func, PyObject *arg, PyObject **old_traceobj)
{
assert(is_tstate_valid(tstate));
/* The caller must hold the GIL */
assert(PyGILState_Check());
/* Call _PySys_Audit() in the context of the current thread state,
even if tstate is not the current thread state. */
PyThreadState *current_tstate = _PyThreadState_GET();
if (_PySys_Audit(current_tstate, "sys.settrace", NULL) < 0) {
return -1;
}
assert(tstate->interp->sys_tracing_threads >= 0);
*old_traceobj = NULL;
/* Setup PEP 669 monitoring callbacks and events. */
if (!tstate->interp->sys_trace_initialized) {
tstate->interp->sys_trace_initialized = true;
@ -553,14 +562,39 @@ _PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
int delta = (func != NULL) - (tstate->c_tracefunc != NULL);
tstate->c_tracefunc = func;
PyObject *old_traceobj = tstate->c_traceobj;
*old_traceobj = tstate->c_traceobj;
tstate->c_traceobj = Py_XNewRef(arg);
Py_XDECREF(old_traceobj);
tstate->interp->sys_tracing_threads += delta;
assert(tstate->interp->sys_tracing_threads >= 0);
return tstate->interp->sys_tracing_threads;
}
int
_PyEval_SetTrace(PyThreadState *tstate, Py_tracefunc func, PyObject *arg)
{
assert(is_tstate_valid(tstate));
/* The caller must hold the GIL */
assert(PyGILState_Check());
/* Call _PySys_Audit() in the context of the current thread state,
even if tstate is not the current thread state. */
PyThreadState *current_tstate = _PyThreadState_GET();
if (_PySys_Audit(current_tstate, "sys.settrace", NULL) < 0) {
return -1;
}
assert(tstate->interp->sys_tracing_threads >= 0);
// needs to be decref'd outside of the lock
PyObject *old_traceobj;
LOCK_SETUP();
Py_ssize_t tracing_threads = setup_tracing(tstate, func, arg, &old_traceobj);
UNLOCK_SETUP();
Py_XDECREF(old_traceobj);
if (tracing_threads < 0) {
return -1;
}
uint32_t events = 0;
if (tstate->interp->sys_tracing_threads) {
if (tracing_threads) {
events =
(1 << PY_MONITORING_EVENT_PY_START) | (1 << PY_MONITORING_EVENT_PY_RESUME) |
(1 << PY_MONITORING_EVENT_PY_RETURN) | (1 << PY_MONITORING_EVENT_PY_YIELD) |