https://github.com/python/cpython/commit/3193cb5ef87b77158d5c9bef99ae445cb82727de
commit: 3193cb5ef87b77158d5c9bef99ae445cb82727de
branch: main
author: Victor Stinner <[email protected]>
committer: vstinner <[email protected]>
date: 2025-01-16T13:53:18+01:00
summary:
gh-128679: Fix tracemalloc.stop() race conditions (#128893)
tracemalloc_alloc(), tracemalloc_realloc(), tracemalloc_free(),
_PyTraceMalloc_TraceRef() and _PyTraceMalloc_GetMemory() now check
'tracemalloc_config.tracing' after calling TABLES_LOCK().
_PyTraceMalloc_TraceRef() now always returns 0.
files:
A Misc/NEWS.d/next/Library/2025-01-15-21-41-51.gh-issue-128679.tq10F2.rst
M Lib/test/test_tracemalloc.py
M Modules/_testcapimodule.c
M Python/tracemalloc.c
diff --git a/Lib/test/test_tracemalloc.py b/Lib/test/test_tracemalloc.py
index 5755f7697de91a..da2db28775578a 100644
--- a/Lib/test/test_tracemalloc.py
+++ b/Lib/test/test_tracemalloc.py
@@ -7,8 +7,9 @@
from test.support.script_helper import (assert_python_ok,
assert_python_failure,
interpreter_requires_environment)
from test import support
-from test.support import os_helper
from test.support import force_not_colorized
+from test.support import os_helper
+from test.support import threading_helper
try:
import _testcapi
@@ -952,7 +953,6 @@ def check_env_var_invalid(self, nframe):
return
self.fail(f"unexpected output: {stderr!a}")
-
def test_env_var_invalid(self):
for nframe in INVALID_NFRAME:
with self.subTest(nframe=nframe):
@@ -1101,6 +1101,12 @@ def test_stop_untrack(self):
with self.assertRaises(RuntimeError):
self.untrack()
+ @unittest.skipIf(_testcapi is None, 'need _testcapi')
+ @threading_helper.requires_working_threading()
+ def test_tracemalloc_track_race(self):
+ # gh-128679: Test fix for tracemalloc.stop() race condition
+ _testcapi.tracemalloc_track_race()
+
if __name__ == "__main__":
unittest.main()
diff --git
a/Misc/NEWS.d/next/Library/2025-01-15-21-41-51.gh-issue-128679.tq10F2.rst
b/Misc/NEWS.d/next/Library/2025-01-15-21-41-51.gh-issue-128679.tq10F2.rst
new file mode 100644
index 00000000000000..5c108da5703c00
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2025-01-15-21-41-51.gh-issue-128679.tq10F2.rst
@@ -0,0 +1,3 @@
+:mod:`tracemalloc`: Fix race conditions when :func:`tracemalloc.stop` is
+called by a thread, while other threads are tracing memory allocations.
+Patch by Victor Stinner.
diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c
index a0a1f8af6710a3..7d304add5999d1 100644
--- a/Modules/_testcapimodule.c
+++ b/Modules/_testcapimodule.c
@@ -3435,6 +3435,104 @@ code_offset_to_line(PyObject* self, PyObject* const*
args, Py_ssize_t nargsf)
return PyLong_FromInt32(PyCode_Addr2Line(code, offset));
}
+
+static void
+tracemalloc_track_race_thread(void *data)
+{
+ PyTraceMalloc_Track(123, 10, 1);
+
+ PyThread_type_lock lock = (PyThread_type_lock)data;
+ PyThread_release_lock(lock);
+}
+
+// gh-128679: Test fix for tracemalloc.stop() race condition
+static PyObject *
+tracemalloc_track_race(PyObject *self, PyObject *args)
+{
+#define NTHREAD 50
+ PyObject *tracemalloc = NULL;
+ PyObject *stop = NULL;
+ PyThread_type_lock locks[NTHREAD];
+ memset(locks, 0, sizeof(locks));
+
+ // Call tracemalloc.start()
+ tracemalloc = PyImport_ImportModule("tracemalloc");
+ if (tracemalloc == NULL) {
+ goto error;
+ }
+ PyObject *start = PyObject_GetAttrString(tracemalloc, "start");
+ if (start == NULL) {
+ goto error;
+ }
+ PyObject *res = PyObject_CallNoArgs(start);
+ Py_DECREF(start);
+ if (res == NULL) {
+ goto error;
+ }
+ Py_DECREF(res);
+
+ stop = PyObject_GetAttrString(tracemalloc, "stop");
+ Py_CLEAR(tracemalloc);
+ if (stop == NULL) {
+ goto error;
+ }
+
+ // Start threads
+ for (size_t i = 0; i < NTHREAD; i++) {
+ PyThread_type_lock lock = PyThread_allocate_lock();
+ if (!lock) {
+ PyErr_NoMemory();
+ goto error;
+ }
+ locks[i] = lock;
+ PyThread_acquire_lock(lock, 1);
+
+ unsigned long thread;
+ thread = PyThread_start_new_thread(tracemalloc_track_race_thread,
+ (void*)lock);
+ if (thread == (unsigned long)-1) {
+ PyErr_SetString(PyExc_RuntimeError, "can't start new thread");
+ goto error;
+ }
+ }
+
+ // Call tracemalloc.stop() while threads are running
+ res = PyObject_CallNoArgs(stop);
+ Py_CLEAR(stop);
+ if (res == NULL) {
+ goto error;
+ }
+ Py_DECREF(res);
+
+ // Wait until threads complete with the GIL released
+ Py_BEGIN_ALLOW_THREADS
+ for (size_t i = 0; i < NTHREAD; i++) {
+ PyThread_type_lock lock = locks[i];
+ PyThread_acquire_lock(lock, 1);
+ PyThread_release_lock(lock);
+ }
+ Py_END_ALLOW_THREADS
+
+ // Free threads locks
+ for (size_t i=0; i < NTHREAD; i++) {
+ PyThread_type_lock lock = locks[i];
+ PyThread_free_lock(lock);
+ }
+ Py_RETURN_NONE;
+
+error:
+ Py_CLEAR(tracemalloc);
+ Py_CLEAR(stop);
+ for (size_t i=0; i < NTHREAD; i++) {
+ PyThread_type_lock lock = locks[i];
+ if (lock) {
+ PyThread_free_lock(lock);
+ }
+ }
+ return NULL;
+#undef NTHREAD
+}
+
static PyMethodDef TestMethods[] = {
{"set_errno", set_errno, METH_VARARGS},
{"test_config", test_config, METH_NOARGS},
@@ -3578,6 +3676,7 @@ static PyMethodDef TestMethods[] = {
{"type_freeze", type_freeze, METH_VARARGS},
{"test_atexit", test_atexit, METH_NOARGS},
{"code_offset_to_line", _PyCFunction_CAST(code_offset_to_line),
METH_FASTCALL},
+ {"tracemalloc_track_race", tracemalloc_track_race, METH_NOARGS},
{NULL, NULL} /* sentinel */
};
diff --git a/Python/tracemalloc.c b/Python/tracemalloc.c
index 68b641c51868b9..919c564ee72967 100644
--- a/Python/tracemalloc.c
+++ b/Python/tracemalloc.c
@@ -567,11 +567,14 @@ tracemalloc_alloc(int need_gil, int use_calloc,
}
TABLES_LOCK();
- if (ADD_TRACE(ptr, nelem * elsize) < 0) {
- // Failed to allocate a trace for the new memory block
- alloc->free(alloc->ctx, ptr);
- ptr = NULL;
+ if (tracemalloc_config.tracing) {
+ if (ADD_TRACE(ptr, nelem * elsize) < 0) {
+ // Failed to allocate a trace for the new memory block
+ alloc->free(alloc->ctx, ptr);
+ ptr = NULL;
+ }
}
+ // else: gh-128679: tracemalloc.stop() was called by another thread
TABLES_UNLOCK();
if (need_gil) {
@@ -614,6 +617,11 @@ tracemalloc_realloc(int need_gil, void *ctx, void *ptr,
size_t new_size)
}
TABLES_LOCK();
+ if (!tracemalloc_config.tracing) {
+ // gh-128679: tracemalloc.stop() was called by another thread
+ goto unlock;
+ }
+
if (ptr != NULL) {
// An existing memory block has been resized
@@ -646,6 +654,7 @@ tracemalloc_realloc(int need_gil, void *ctx, void *ptr,
size_t new_size)
}
}
+unlock:
TABLES_UNLOCK();
if (need_gil) {
PyGILState_Release(gil_state);
@@ -674,7 +683,12 @@ tracemalloc_free(void *ctx, void *ptr)
}
TABLES_LOCK();
- REMOVE_TRACE(ptr);
+
+ if (tracemalloc_config.tracing) {
+ REMOVE_TRACE(ptr);
+ }
+ // else: gh-128679: tracemalloc.stop() was called by another thread
+
TABLES_UNLOCK();
}
@@ -1312,8 +1326,9 @@ _PyTraceMalloc_TraceRef(PyObject *op, PyRefTracerEvent
event,
assert(PyGILState_Check());
TABLES_LOCK();
- int result = -1;
- assert(tracemalloc_config.tracing);
+ if (!tracemalloc_config.tracing) {
+ goto done;
+ }
PyTypeObject *type = Py_TYPE(op);
const size_t presize = _PyType_PreHeaderSize(type);
@@ -1325,13 +1340,13 @@ _PyTraceMalloc_TraceRef(PyObject *op, PyRefTracerEvent
event,
traceback_t *traceback = traceback_new();
if (traceback != NULL) {
trace->traceback = traceback;
- result = 0;
}
}
/* else: cannot track the object, its memory block size is unknown */
+done:
TABLES_UNLOCK();
- return result;
+ return 0;
}
@@ -1472,13 +1487,19 @@ int _PyTraceMalloc_GetTracebackLimit(void)
size_t
_PyTraceMalloc_GetMemory(void)
{
- size_t size = _Py_hashtable_size(tracemalloc_tracebacks);
- size += _Py_hashtable_size(tracemalloc_filenames);
-
TABLES_LOCK();
- size += _Py_hashtable_size(tracemalloc_traces);
- _Py_hashtable_foreach(tracemalloc_domains,
- tracemalloc_get_tracemalloc_memory_cb, &size);
+ size_t size;
+ if (tracemalloc_config.tracing) {
+ size = _Py_hashtable_size(tracemalloc_tracebacks);
+ size += _Py_hashtable_size(tracemalloc_filenames);
+
+ size += _Py_hashtable_size(tracemalloc_traces);
+ _Py_hashtable_foreach(tracemalloc_domains,
+ tracemalloc_get_tracemalloc_memory_cb, &size);
+ }
+ else {
+ size = 0;
+ }
TABLES_UNLOCK();
return size;
}
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