GH-140643: Add <native> and <GC> frames to the sampling profiler (#141108)

- Introduce a new field in the GC state to store the frame that initiated garbage collection.
- Update RemoteUnwinder to include options for including "<native>" and "<GC>" frames in the stack trace.
- Modify the sampling profiler to accept parameters for controlling the inclusion of native and GC frames.
- Enhance the stack collector to properly format and append these frames during profiling.
- Add tests to verify the correct behavior of the profiler with respect to native and GC frames, including options to exclude them.

Co-authored-by: Pablo Galindo Salgado <pablogsal@gmail.com>

Doc/library/profile.rst

@@ -265,6 +265,14 @@ Profile with real-time sampling statistics::
 
    Sample all threads in the process instead of just the main thread
 
+.. option:: --native
+
+   Include artificial ``<native>`` frames to denote calls to non-Python code.
+
+.. option:: --no-gc
+
+   Don't include artificial ``<GC>`` frames to denote active garbage collection.
+
 .. option:: --realtime-stats
 
    Print real-time sampling statistics during profiling
@@ -349,7 +357,7 @@ This section documents the programmatic interface for the :mod:`!profiling.sampl
 For command-line usage, see :ref:`sampling-profiler-cli`. For conceptual information
 about statistical profiling, see :ref:`statistical-profiling`
 
-.. function:: sample(pid, *, sort=2, sample_interval_usec=100, duration_sec=10, filename=None, all_threads=False, limit=None, show_summary=True, output_format="pstats", realtime_stats=False)
+.. function:: sample(pid, *, sort=2, sample_interval_usec=100, duration_sec=10, filename=None, all_threads=False, limit=None, show_summary=True, output_format="pstats", realtime_stats=False, native=False, gc=True)
 
    Sample a Python process and generate profiling data.
 
@@ -367,6 +375,8 @@ about statistical profiling, see :ref:`statistical-profiling`
    :param bool show_summary: Whether to show summary statistics (default: True)
    :param str output_format: Output format - 'pstats' or 'collapsed' (default: 'pstats')
    :param bool realtime_stats: Whether to display real-time statistics (default: False)
+   :param bool native: Whether to include ``<native>`` frames (default: False)
+   :param bool gc: Whether to include ``<GC>`` frames (default: True)
 
    :raises ValueError: If output_format is not 'pstats' or 'collapsed'
 

Include/internal/pycore_debug_offsets.h

@@ -212,6 +212,7 @@ typedef struct _Py_DebugOffsets {
     struct _gc {
         uint64_t size;
         uint64_t collecting;
+        uint64_t frame;
     } gc;
 
     // Generator object offset;
@@ -355,6 +356,7 @@ typedef struct _Py_DebugOffsets {
     .gc = { \
         .size = sizeof(struct _gc_runtime_state), \
         .collecting = offsetof(struct _gc_runtime_state, collecting), \
+        .frame = offsetof(struct _gc_runtime_state, frame), \
     }, \
     .gen_object = { \
         .size = sizeof(PyGenObject), \

Include/internal/pycore_global_objects_fini_generated.h

@@ -1326,10 +1326,12 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(dot_locals));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(empty));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(format));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(gc));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(generic_base));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(json_decoder));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(kwdefaults));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(list_err));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(native));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(str_replace_inf));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(type_params));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_STR(utf_8));
@@ -1763,6 +1765,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(fullerror));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(func));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(future));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(gc));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(generation));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(get));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(get_debug));
@@ -1906,6 +1909,7 @@ _PyStaticObjects_CheckRefcnt(PyInterpreterState *interp) {
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(name_from));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(namespace_separator));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(namespaces));
+    _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(native));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(ndigits));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(nested));
     _PyStaticObject_CheckRefcnt((PyObject *)&_Py_ID(new_file_name));

Include/internal/pycore_global_strings.h

@@ -46,10 +46,12 @@ struct _Py_global_strings {
         STRUCT_FOR_STR(dot_locals, ".<locals>")
         STRUCT_FOR_STR(empty, "")
         STRUCT_FOR_STR(format, ".format")
+        STRUCT_FOR_STR(gc, "<GC>")
         STRUCT_FOR_STR(generic_base, ".generic_base")
         STRUCT_FOR_STR(json_decoder, "json.decoder")
         STRUCT_FOR_STR(kwdefaults, ".kwdefaults")
         STRUCT_FOR_STR(list_err, "list index out of range")
+        STRUCT_FOR_STR(native, "<native>")
         STRUCT_FOR_STR(str_replace_inf, "1e309")
         STRUCT_FOR_STR(type_params, ".type_params")
         STRUCT_FOR_STR(utf_8, "utf-8")
@@ -486,6 +488,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(fullerror)
         STRUCT_FOR_ID(func)
         STRUCT_FOR_ID(future)
+        STRUCT_FOR_ID(gc)
         STRUCT_FOR_ID(generation)
         STRUCT_FOR_ID(get)
         STRUCT_FOR_ID(get_debug)
@@ -629,6 +632,7 @@ struct _Py_global_strings {
         STRUCT_FOR_ID(name_from)
         STRUCT_FOR_ID(namespace_separator)
         STRUCT_FOR_ID(namespaces)
+        STRUCT_FOR_ID(native)
         STRUCT_FOR_ID(ndigits)
         STRUCT_FOR_ID(nested)
         STRUCT_FOR_ID(new_file_name)

Include/internal/pycore_interp_structs.h

@@ -212,6 +212,9 @@ struct _gc_runtime_state {
     struct gc_generation_stats generation_stats[NUM_GENERATIONS];
     /* true if we are currently running the collector */
     int collecting;
+    // The frame that started the current collection. It might be NULL even when
+    // collecting (if no Python frame is running):
+    _PyInterpreterFrame *frame;
     /* list of uncollectable objects */
     PyObject *garbage;
     /* a list of callbacks to be invoked when collection is performed */

Include/internal/pycore_interpframe_structs.h

@@ -24,7 +24,6 @@ enum _frameowner {
     FRAME_OWNED_BY_GENERATOR = 1,
     FRAME_OWNED_BY_FRAME_OBJECT = 2,
     FRAME_OWNED_BY_INTERPRETER = 3,
-    FRAME_OWNED_BY_CSTACK = 4,
 };
 
 struct _PyInterpreterFrame {

Include/internal/pycore_runtime_init_generated.h

@@ -1321,10 +1321,12 @@ extern "C" {
     INIT_STR(dot_locals, ".<locals>"), \
     INIT_STR(empty, ""), \
     INIT_STR(format, ".format"), \
+    INIT_STR(gc, "<GC>"), \
     INIT_STR(generic_base, ".generic_base"), \
     INIT_STR(json_decoder, "json.decoder"), \
     INIT_STR(kwdefaults, ".kwdefaults"), \
     INIT_STR(list_err, "list index out of range"), \
+    INIT_STR(native, "<native>"), \
     INIT_STR(str_replace_inf, "1e309"), \
     INIT_STR(type_params, ".type_params"), \
     INIT_STR(utf_8, "utf-8"), \
@@ -1761,6 +1763,7 @@ extern "C" {
     INIT_ID(fullerror), \
     INIT_ID(func), \
     INIT_ID(future), \
+    INIT_ID(gc), \
     INIT_ID(generation), \
     INIT_ID(get), \
     INIT_ID(get_debug), \
@@ -1904,6 +1907,7 @@ extern "C" {
     INIT_ID(name_from), \
     INIT_ID(namespace_separator), \
     INIT_ID(namespaces), \
+    INIT_ID(native), \
     INIT_ID(ndigits), \
     INIT_ID(nested), \
     INIT_ID(new_file_name), \

Include/internal/pycore_unicodeobject_generated.h

@@ -1732,6 +1732,10 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
     assert(PyUnicode_GET_LENGTH(string) != 1);
+    string = &_Py_ID(gc);
+    _PyUnicode_InternStatic(interp, &string);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    assert(PyUnicode_GET_LENGTH(string) != 1);
     string = &_Py_ID(generation);
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
@@ -2304,6 +2308,10 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
     assert(PyUnicode_GET_LENGTH(string) != 1);
+    string = &_Py_ID(native);
+    _PyUnicode_InternStatic(interp, &string);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    assert(PyUnicode_GET_LENGTH(string) != 1);
     string = &_Py_ID(ndigits);
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
@@ -3236,6 +3244,10 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
     assert(PyUnicode_GET_LENGTH(string) != 1);
+    string = &_Py_STR(gc);
+    _PyUnicode_InternStatic(interp, &string);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    assert(PyUnicode_GET_LENGTH(string) != 1);
     string = &_Py_STR(anon_null);
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
@@ -3260,6 +3272,10 @@ _PyUnicode_InitStaticStrings(PyInterpreterState *interp) {
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));
     assert(PyUnicode_GET_LENGTH(string) != 1);
+    string = &_Py_STR(native);
+    _PyUnicode_InternStatic(interp, &string);
+    assert(_PyUnicode_CheckConsistency(string, 1));
+    assert(PyUnicode_GET_LENGTH(string) != 1);
     string = &_Py_STR(anon_setcomp);
     _PyUnicode_InternStatic(interp, &string);
     assert(_PyUnicode_CheckConsistency(string, 1));

Lib/profiling/sampling/flamegraph.js

@@ -151,17 +151,22 @@ function createPythonTooltip(data) {
     const funcname = resolveString(d.data.funcname) || resolveString(d.data.name);
     const filename = resolveString(d.data.filename) || "";
 
+    // Don't show file location for special frames like <GC> and <native>
+    const isSpecialFrame = filename === "~";
+    const fileLocationHTML = isSpecialFrame ? "" : `
+        <div style="color: #5a6c7d; font-size: 13px; margin-bottom: 12px;
+                    font-family: monospace; background: #f8f9fa;
+                    padding: 4px 8px; border-radius: 4px; word-break: break-all; overflow-wrap: break-word;">
+          ${filename}${d.data.lineno ? ":" + d.data.lineno : ""}
+        </div>`;
+
     const tooltipHTML = `
       <div>
         <div style="color: #3776ab; font-weight: 600; font-size: 16px;
                     margin-bottom: 8px; line-height: 1.3; word-break: break-word; overflow-wrap: break-word;">
           ${funcname}
         </div>
-        <div style="color: #5a6c7d; font-size: 13px; margin-bottom: 12px;
+        ${fileLocationHTML}
-                    font-family: monospace; background: #f8f9fa;
-                    padding: 4px 8px; border-radius: 4px; word-break: break-all; overflow-wrap: break-word;">
-          ${filename}${d.data.lineno ? ":" + d.data.lineno : ""}
-        </div>
         <div style="display: grid; grid-template-columns: auto 1fr;
                     gap: 8px 16px; font-size: 14px;">
           <span style="color: #5a6c7d; font-weight: 500;">Execution Time:</span>
@@ -474,14 +479,23 @@ function populateStats(data) {
     if (i < hotSpots.length && hotSpots[i]) {
       const hotspot = hotSpots[i];
       const filename = hotspot.filename || 'unknown';
-      const basename = filename !== 'unknown' ? filename.split('/').pop() : 'unknown';
       const lineno = hotspot.lineno ?? '?';
       let funcDisplay = hotspot.funcname || 'unknown';
       if (funcDisplay.length > 35) {
         funcDisplay = funcDisplay.substring(0, 32) + '...';
       }
 
-      document.getElementById(`hotspot-file-${num}`).textContent = `${basename}:${lineno}`;
+      // Don't show file:line for special frames like <GC> and <native>
+      const isSpecialFrame = filename === '~' && (lineno === 0 || lineno === '?');
+      let fileDisplay;
+      if (isSpecialFrame) {
+        fileDisplay = '--';
+      } else {
+        const basename = filename !== 'unknown' ? filename.split('/').pop() : 'unknown';
+        fileDisplay = `${basename}:${lineno}`;
+      }
+
+      document.getElementById(`hotspot-file-${num}`).textContent = fileDisplay;
       document.getElementById(`hotspot-func-${num}`).textContent = funcDisplay;
       document.getElementById(`hotspot-detail-${num}`).textContent = `${hotspot.directPercent.toFixed(1)}% samples (${hotspot.directSamples.toLocaleString()})`;
     } else {

Lib/profiling/sampling/sample.py

@@ -137,19 +137,19 @@ def _run_with_sync(original_cmd):
 
 
 class SampleProfiler:
-    def __init__(self, pid, sample_interval_usec, all_threads, *, mode=PROFILING_MODE_WALL, skip_non_matching_threads=True):
+    def __init__(self, pid, sample_interval_usec, all_threads, *, mode=PROFILING_MODE_WALL, native=False, gc=True, skip_non_matching_threads=True):
         self.pid = pid
         self.sample_interval_usec = sample_interval_usec
         self.all_threads = all_threads
         if _FREE_THREADED_BUILD:
             self.unwinder = _remote_debugging.RemoteUnwinder(
-                self.pid, all_threads=self.all_threads, mode=mode,
+                self.pid, all_threads=self.all_threads, mode=mode, native=native, gc=gc,
                 skip_non_matching_threads=skip_non_matching_threads
             )
         else:
             only_active_threads = bool(self.all_threads)
             self.unwinder = _remote_debugging.RemoteUnwinder(
-                self.pid, only_active_thread=only_active_threads, mode=mode,
+                self.pid, only_active_thread=only_active_threads, mode=mode, native=native, gc=gc,
                 skip_non_matching_threads=skip_non_matching_threads
             )
         # Track sample intervals and total sample count
@@ -616,6 +616,8 @@ def sample(
     output_format="pstats",
     realtime_stats=False,
     mode=PROFILING_MODE_WALL,
+    native=False,
+    gc=True,
 ):
     # PROFILING_MODE_ALL implies no skipping at all
     if mode == PROFILING_MODE_ALL:
@@ -627,7 +629,7 @@ def sample(
         skip_idle = mode != PROFILING_MODE_WALL
 
     profiler = SampleProfiler(
-        pid, sample_interval_usec, all_threads=all_threads, mode=mode,
+        pid, sample_interval_usec, all_threads=all_threads, mode=mode, native=native, gc=gc,
         skip_non_matching_threads=skip_non_matching_threads
     )
     profiler.realtime_stats = realtime_stats
@@ -717,6 +719,8 @@ def wait_for_process_and_sample(pid, sort_value, args):
         output_format=args.format,
         realtime_stats=args.realtime_stats,
         mode=mode,
+        native=args.native,
+        gc=args.gc,
     )
 
 
@@ -767,9 +771,19 @@ def main():
     sampling_group.add_argument(
         "--realtime-stats",
         action="store_true",
-        default=False,
         help="Print real-time sampling statistics (Hz, mean, min, max, stdev) during profiling",
     )
+    sampling_group.add_argument(
+        "--native",
+        action="store_true",
+        help="Include artificial \"<native>\" frames to denote calls to non-Python code.",
+    )
+    sampling_group.add_argument(
+        "--no-gc",
+        action="store_false",
+        dest="gc",
+        help="Don't include artificial \"<GC>\" frames to denote active garbage collection.",
+    )
 
     # Mode options
     mode_group = parser.add_argument_group("Mode options")
@@ -934,6 +948,8 @@ def main():
             output_format=args.format,
             realtime_stats=args.realtime_stats,
             mode=mode,
+            native=args.native,
+            gc=args.gc,
         )
     elif args.module or args.args:
         if args.module:

Lib/profiling/sampling/stack_collector.py

@@ -36,10 +36,16 @@ def process_frames(self, frames, thread_id):
     def export(self, filename):
         lines = []
         for (call_tree, thread_id), count in self.stack_counter.items():
-            stack_str = ";".join(
+            parts = [f"tid:{thread_id}"]
-                f"{os.path.basename(f[0])}:{f[2]}:{f[1]}" for f in call_tree
+            for file, line, func in call_tree:
-            )
+                # This is what pstats does for "special" frames:
-            lines.append((f"tid:{thread_id};{stack_str}", count))
+                if file == "~" and line == 0:
+                    part = func
+                else:
+                    part = f"{os.path.basename(file)}:{func}:{line}"
+                parts.append(part)
+            stack_str = ";".join(parts)
+            lines.append((stack_str, count))
 
         lines.sort(key=lambda x: (-x[1], x[0]))
 
@@ -98,6 +104,10 @@ def export(self, filename):
     def _format_function_name(func):
         filename, lineno, funcname = func
 
+        # Special frames like <GC> and <native> should not show file:line
+        if filename == "~" and lineno == 0:
+            return funcname
+
         if len(filename) > 50:
             parts = filename.split("/")
             if len(parts) > 2:

Lib/test/test_external_inspection.py

@@ -159,6 +159,8 @@ def foo():
                 FrameInfo([script_name, 12, "baz"]),
                 FrameInfo([script_name, 9, "bar"]),
                 FrameInfo([threading.__file__, ANY, "Thread.run"]),
+                FrameInfo([threading.__file__, ANY, "Thread._bootstrap_inner"]),
+                FrameInfo([threading.__file__, ANY, "Thread._bootstrap"]),
             ]
             # Is possible that there are more threads, so we check that the
             # expected stack traces are in the result (looking at you Windows!)

Lib/test/test_profiling/test_sampling_profiler.py

@@ -2025,7 +2025,6 @@ def test_sample_target_script(self):
         # Should see some of our test functions
         self.assertIn("slow_fibonacci", output)
 
-
     def test_sample_target_module(self):
         tempdir = tempfile.TemporaryDirectory(delete=False)
         self.addCleanup(lambda x: shutil.rmtree(x), tempdir.name)
@@ -2264,7 +2263,9 @@ def test_cli_module_argument_parsing(self):
                 show_summary=True,
                 output_format="pstats",
                 realtime_stats=False,
-                mode=0
+                mode=0,
+                native=False,
+                gc=True,
             )
 
     @unittest.skipIf(is_emscripten, "socket.SO_REUSEADDR does not exist")
@@ -2292,7 +2293,9 @@ def test_cli_module_with_arguments(self):
                 show_summary=True,
                 output_format="pstats",
                 realtime_stats=False,
-                mode=0
+                mode=0,
+                native=False,
+                gc=True,
             )
 
     @unittest.skipIf(is_emscripten, "socket.SO_REUSEADDR does not exist")
@@ -2320,7 +2323,9 @@ def test_cli_script_argument_parsing(self):
                 show_summary=True,
                 output_format="pstats",
                 realtime_stats=False,
-                mode=0
+                mode=0,
+                native=False,
+                gc=True,
             )
 
     @unittest.skipIf(is_emscripten, "socket.SO_REUSEADDR does not exist")
@@ -2420,7 +2425,9 @@ def test_cli_module_with_profiler_options(self):
                 show_summary=True,
                 output_format="pstats",
                 realtime_stats=False,
-                mode=0
+                mode=0,
+                native=False,
+                gc=True,
             )
 
     @unittest.skipIf(is_emscripten, "socket.SO_REUSEADDR does not exist")
@@ -2454,7 +2461,9 @@ def test_cli_script_with_profiler_options(self):
                 show_summary=True,
                 output_format="collapsed",
                 realtime_stats=False,
-                mode=0
+                mode=0,
+                native=False,
+                gc=True,
             )
 
     def test_cli_empty_module_name(self):
@@ -2666,7 +2675,9 @@ def test_argument_parsing_basic(self):
                 show_summary=True,
                 output_format="pstats",
                 realtime_stats=False,
-                mode=0
+                mode=0,
+                native=False,
+                gc=True,
             )
 
     def test_sort_options(self):
@@ -3121,6 +3132,187 @@ def test_parse_mode_function(self):
 
 @requires_subprocess()
 @skip_if_not_supported
+class TestGCFrameTracking(unittest.TestCase):
+    """Tests for GC frame tracking in the sampling profiler."""
+
+    @classmethod
+    def setUpClass(cls):
+        """Create a static test script with GC frames and CPU-intensive work."""
+        cls.gc_test_script = '''
+import gc
+
+class ExpensiveGarbage:
+    """Class that triggers GC with expensive finalizer (callback)."""
+    def __init__(self):
+        self.cycle = self
+
+    def __del__(self):
+        # CPU-intensive work in the finalizer callback
+        result = 0
+        for i in range(100000):
+            result += i * i
+            if i % 1000 == 0:
+                result = result % 1000000
+
+def main_loop():
+    """Main loop that triggers GC with expensive callback."""
+    while True:
+        ExpensiveGarbage()
+        gc.collect()
+
+if __name__ == "__main__":
+    main_loop()
+'''
+
+    def test_gc_frames_enabled(self):
+        """Test that GC frames appear when gc tracking is enabled."""
+        with (
+            test_subprocess(self.gc_test_script) as subproc,
+            io.StringIO() as captured_output,
+            mock.patch("sys.stdout", captured_output),
+        ):
+            try:
+                profiling.sampling.sample.sample(
+                    subproc.process.pid,
+                    duration_sec=1,
+                    sample_interval_usec=5000,
+                    show_summary=False,
+                    native=False,
+                    gc=True,
+                )
+            except PermissionError:
+                self.skipTest("Insufficient permissions for remote profiling")
+
+            output = captured_output.getvalue()
+
+        # Should capture samples
+        self.assertIn("Captured", output)
+        self.assertIn("samples", output)
+
+        # GC frames should be present
+        self.assertIn("<GC>", output)
+
+    def test_gc_frames_disabled(self):
+        """Test that GC frames do not appear when gc tracking is disabled."""
+        with (
+            test_subprocess(self.gc_test_script) as subproc,
+            io.StringIO() as captured_output,
+            mock.patch("sys.stdout", captured_output),
+        ):
+            try:
+                profiling.sampling.sample.sample(
+                    subproc.process.pid,
+                    duration_sec=1,
+                    sample_interval_usec=5000,
+                    show_summary=False,
+                    native=False,
+                    gc=False,
+                )
+            except PermissionError:
+                self.skipTest("Insufficient permissions for remote profiling")
+
+            output = captured_output.getvalue()
+
+        # Should capture samples
+        self.assertIn("Captured", output)
+        self.assertIn("samples", output)
+
+        # GC frames should NOT be present
+        self.assertNotIn("<GC>", output)
+
+
+@requires_subprocess()
+@skip_if_not_supported
+class TestNativeFrameTracking(unittest.TestCase):
+    """Tests for native frame tracking in the sampling profiler."""
+
+    @classmethod
+    def setUpClass(cls):
+        """Create a static test script with native frames and CPU-intensive work."""
+        cls.native_test_script = '''
+import operator
+
+def main_loop():
+    while True:
+        # Native code in the middle of the stack:
+        operator.call(inner)
+
+def inner():
+    # Python code at the top of the stack:
+    for _ in range(1_000_0000):
+        pass
+
+if __name__ == "__main__":
+    main_loop()
+'''
+
+    def test_native_frames_enabled(self):
+        """Test that native frames appear when native tracking is enabled."""
+        collapsed_file = tempfile.NamedTemporaryFile(
+            suffix=".txt", delete=False
+        )
+        self.addCleanup(close_and_unlink, collapsed_file)
+
+        with (
+            test_subprocess(self.native_test_script) as subproc,
+        ):
+            # Suppress profiler output when testing file export
+            with (
+                io.StringIO() as captured_output,
+                mock.patch("sys.stdout", captured_output),
+            ):
+                try:
+                    profiling.sampling.sample.sample(
+                        subproc.process.pid,
+                        duration_sec=1,
+                        filename=collapsed_file.name,
+                        output_format="collapsed",
+                        sample_interval_usec=1000,
+                        native=True,
+                    )
+                except PermissionError:
+                    self.skipTest("Insufficient permissions for remote profiling")
+
+            # Verify file was created and contains valid data
+            self.assertTrue(os.path.exists(collapsed_file.name))
+            self.assertGreater(os.path.getsize(collapsed_file.name), 0)
+
+            # Check file format
+            with open(collapsed_file.name, "r") as f:
+                content = f.read()
+
+        lines = content.strip().split("\n")
+        self.assertGreater(len(lines), 0)
+
+        stacks = [line.rsplit(" ", 1)[0] for line in lines]
+
+        # Most samples should have native code in the middle of the stack:
+        self.assertTrue(any(";<native>;" in stack for stack in stacks))
+
+        # No samples should have native code at the top of the stack:
+        self.assertFalse(any(stack.endswith(";<native>") for stack in stacks))
+
+    def test_native_frames_disabled(self):
+        """Test that native frames do not appear when native tracking is disabled."""
+        with (
+            test_subprocess(self.native_test_script) as subproc,
+            io.StringIO() as captured_output,
+            mock.patch("sys.stdout", captured_output),
+        ):
+            try:
+                profiling.sampling.sample.sample(
+                    subproc.process.pid,
+                    duration_sec=1,
+                    sample_interval_usec=5000,
+                    show_summary=False,
+                )
+            except PermissionError:
+                self.skipTest("Insufficient permissions for remote profiling")
+            output = captured_output.getvalue()
+        # Native frames should NOT be present:
+        self.assertNotIn("<native>", output)
+
+
 class TestProcessPoolExecutorSupport(unittest.TestCase):
     """
     Test that ProcessPoolExecutor works correctly with profiling.sampling.
@@ -3161,7 +3353,5 @@ def worker(x):
 
         self.assertIn("Results: [2, 4, 6]", stdout)
         self.assertNotIn("Can't pickle", stderr)
-
-
 if __name__ == "__main__":
     unittest.main()

Misc/NEWS.d/next/Core_and_Builtins/2025-11-05-19-50-37.gh-issue-140643.QCEOqG.rst

@@ -0,0 +1,3 @@
+Add support for ``<GC>`` and ``<native>`` frames to
+:mod:`!profiling.sampling` output to denote active garbage collection and
+calls to native code.

Modules/_remote_debugging_module.c

@@ -26,8 +26,9 @@
 #include "Python.h"
 #include <internal/pycore_debug_offsets.h>  // _Py_DebugOffsets
 #include <internal/pycore_frame.h>          // FRAME_SUSPENDED_YIELD_FROM
-#include <internal/pycore_interpframe.h>    // FRAME_OWNED_BY_CSTACK
+#include <internal/pycore_interpframe.h>    // FRAME_OWNED_BY_INTERPRETER
 #include <internal/pycore_llist.h>          // struct llist_node
+#include <internal/pycore_long.h>           // _PyLong_GetZero
 #include <internal/pycore_stackref.h>       // Py_TAG_BITS
 #include "../Python/remote_debug.h"
 
@@ -92,14 +93,16 @@ typedef enum _WIN32_THREADSTATE {
 #endif
 
 #ifdef Py_GIL_DISABLED
-#define INTERP_STATE_MIN_SIZE MAX(MAX(MAX(offsetof(PyInterpreterState, _code_object_generation) + sizeof(uint64_t), \
+#define INTERP_STATE_MIN_SIZE MAX(MAX(MAX(MAX(offsetof(PyInterpreterState, _code_object_generation) + sizeof(uint64_t), \
-                                          offsetof(PyInterpreterState, tlbc_indices.tlbc_generation) + sizeof(uint32_t)), \
+                                              offsetof(PyInterpreterState, tlbc_indices.tlbc_generation) + sizeof(uint32_t)), \
-                                      offsetof(PyInterpreterState, threads.head) + sizeof(void*)), \
+                                          offsetof(PyInterpreterState, threads.head) + sizeof(void*)), \
-                                  offsetof(PyInterpreterState, _gil.last_holder) + sizeof(PyThreadState*))
+                                      offsetof(PyInterpreterState, _gil.last_holder) + sizeof(PyThreadState*)), \
+                                  offsetof(PyInterpreterState, gc.frame) + sizeof(_PyInterpreterFrame *))
 #else
-#define INTERP_STATE_MIN_SIZE MAX(MAX(offsetof(PyInterpreterState, _code_object_generation) + sizeof(uint64_t), \
+#define INTERP_STATE_MIN_SIZE MAX(MAX(MAX(offsetof(PyInterpreterState, _code_object_generation) + sizeof(uint64_t), \
-                                      offsetof(PyInterpreterState, threads.head) + sizeof(void*)), \
+                                          offsetof(PyInterpreterState, threads.head) + sizeof(void*)), \
-                                  offsetof(PyInterpreterState, _gil.last_holder) + sizeof(PyThreadState*))
+                                      offsetof(PyInterpreterState, _gil.last_holder) + sizeof(PyThreadState*)), \
+                                  offsetof(PyInterpreterState, gc.frame) + sizeof(_PyInterpreterFrame *))
 #endif
 #define INTERP_STATE_BUFFER_SIZE MAX(INTERP_STATE_MIN_SIZE, 256)
 
@@ -276,6 +279,8 @@ typedef struct {
     int only_active_thread;
     int mode;  // Use enum _ProfilingMode values
     int skip_non_matching_threads;  // New option to skip threads that don't match mode
+    int native;
+    int gc;
     RemoteDebuggingState *cached_state;  // Cached module state
 #ifdef Py_GIL_DISABLED
     // TLBC cache invalidation tracking
@@ -1812,6 +1817,25 @@ parse_linetable(const uintptr_t addrq, const char* linetable, int firstlineno, L
  * CODE OBJECT AND FRAME PARSING FUNCTIONS
  * ============================================================================ */
 
+static PyObject *
+make_frame_info(RemoteUnwinderObject *unwinder, PyObject *file, PyObject *line,
+                PyObject *func)
+{
+    RemoteDebuggingState *state = RemoteDebugging_GetStateFromObject((PyObject*)unwinder);
+    PyObject *info = PyStructSequence_New(state->FrameInfo_Type);
+    if (info == NULL) {
+        set_exception_cause(unwinder, PyExc_MemoryError, "Failed to create FrameInfo");
+        return NULL;
+    }
+    Py_INCREF(file);
+    Py_INCREF(line);
+    Py_INCREF(func);
+    PyStructSequence_SetItem(info, 0, file);
+    PyStructSequence_SetItem(info, 1, line);
+    PyStructSequence_SetItem(info, 2, func);
+    return info;
+}
+
 static int
 parse_code_object(RemoteUnwinderObject *unwinder,
                   PyObject **result,
@@ -1825,8 +1849,6 @@ parse_code_object(RemoteUnwinderObject *unwinder,
     PyObject *func = NULL;
     PyObject *file = NULL;
     PyObject *linetable = NULL;
-    PyObject *lineno = NULL;
-    PyObject *tuple = NULL;
 
 #ifdef Py_GIL_DISABLED
     // In free threading builds, code object addresses might have the low bit set
@@ -1948,25 +1970,18 @@ parse_code_object(RemoteUnwinderObject *unwinder,
         info.lineno = -1;
     }
 
-    lineno = PyLong_FromLong(info.lineno);
+    PyObject *lineno = PyLong_FromLong(info.lineno);
     if (!lineno) {
         set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to create line number object");
         goto error;
     }
 
-    RemoteDebuggingState *state = RemoteDebugging_GetStateFromObject((PyObject*)unwinder);
+    PyObject *tuple = make_frame_info(unwinder, meta->file_name, lineno, meta->func_name);
-    tuple = PyStructSequence_New(state->FrameInfo_Type);
+    Py_DECREF(lineno);
     if (!tuple) {
-        set_exception_cause(unwinder, PyExc_MemoryError, "Failed to create FrameInfo for code object");
         goto error;
     }
 
-    Py_INCREF(meta->func_name);
-    Py_INCREF(meta->file_name);
-    PyStructSequence_SetItem(tuple, 0, meta->file_name);
-    PyStructSequence_SetItem(tuple, 1, lineno);
-    PyStructSequence_SetItem(tuple, 2, meta->func_name);
-
     *result = tuple;
     return 0;
 
@@ -1974,8 +1989,6 @@ parse_code_object(RemoteUnwinderObject *unwinder,
     Py_XDECREF(func);
     Py_XDECREF(file);
     Py_XDECREF(linetable);
-    Py_XDECREF(lineno);
-    Py_XDECREF(tuple);
     return -1;
 }
 
@@ -2116,6 +2129,7 @@ parse_frame_from_chunks(
     PyObject **result,
     uintptr_t address,
     uintptr_t *previous_frame,
+    uintptr_t *stackpointer,
     StackChunkList *chunks
 ) {
     void *frame_ptr = find_frame_in_chunks(chunks, address);
@@ -2126,6 +2140,7 @@ parse_frame_from_chunks(
 
     char *frame = (char *)frame_ptr;
     *previous_frame = GET_MEMBER(uintptr_t, frame, unwinder->debug_offsets.interpreter_frame.previous);
+    *stackpointer = GET_MEMBER(uintptr_t, frame, unwinder->debug_offsets.interpreter_frame.stackpointer);
     uintptr_t code_object = GET_MEMBER_NO_TAG(uintptr_t, frame_ptr, unwinder->debug_offsets.interpreter_frame.executable);
     int frame_valid = is_frame_valid(unwinder, (uintptr_t)frame, code_object);
     if (frame_valid != 1) {
@@ -2238,8 +2253,7 @@ is_frame_valid(
 
     void* frame = (void*)frame_addr;
 
-    if (GET_MEMBER(char, frame, unwinder->debug_offsets.interpreter_frame.owner) == FRAME_OWNED_BY_CSTACK ||
+    if (GET_MEMBER(char, frame, unwinder->debug_offsets.interpreter_frame.owner) == FRAME_OWNED_BY_INTERPRETER) {
-        GET_MEMBER(char, frame, unwinder->debug_offsets.interpreter_frame.owner) == FRAME_OWNED_BY_INTERPRETER) {
         return 0;  // C frame
     }
 
@@ -2458,8 +2472,9 @@ process_frame_chain(
     RemoteUnwinderObject *unwinder,
     uintptr_t initial_frame_addr,
     StackChunkList *chunks,
-    PyObject *frame_info
+    PyObject *frame_info,
-) {
+    uintptr_t gc_frame)
+{
     uintptr_t frame_addr = initial_frame_addr;
     uintptr_t prev_frame_addr = 0;
     const size_t MAX_FRAMES = 1024;
@@ -2468,6 +2483,7 @@ process_frame_chain(
     while ((void*)frame_addr != NULL) {
         PyObject *frame = NULL;
         uintptr_t next_frame_addr = 0;
+        uintptr_t stackpointer = 0;
 
         if (++frame_count > MAX_FRAMES) {
             PyErr_SetString(PyExc_RuntimeError, "Too many stack frames (possible infinite loop)");
@@ -2476,7 +2492,7 @@ process_frame_chain(
         }
 
         // Try chunks first, fallback to direct memory read
-        if (parse_frame_from_chunks(unwinder, &frame, frame_addr, &next_frame_addr, chunks) < 0) {
+        if (parse_frame_from_chunks(unwinder, &frame, frame_addr, &next_frame_addr, &stackpointer, chunks) < 0) {
             PyErr_Clear();
             uintptr_t address_of_code_object = 0;
             if (parse_frame_object(unwinder, &frame, frame_addr, &address_of_code_object ,&next_frame_addr) < 0) {
@@ -2484,26 +2500,63 @@ process_frame_chain(
                 return -1;
             }
         }
-
+        if (frame == NULL && PyList_GET_SIZE(frame_info) == 0) {
-        if (!frame) {
+            // If the first frame is missing, the chain is broken:
-            break;
+            const char *e = "Failed to parse initial frame in chain";
-        }
+            PyErr_SetString(PyExc_RuntimeError, e);
-
-        if (prev_frame_addr && frame_addr != prev_frame_addr) {
-            PyErr_Format(PyExc_RuntimeError,
-                        "Broken frame chain: expected frame at 0x%lx, got 0x%lx",
-                        prev_frame_addr, frame_addr);
-            Py_DECREF(frame);
-            set_exception_cause(unwinder, PyExc_RuntimeError, "Frame chain consistency check failed");
             return -1;
         }
-
+        PyObject *extra_frame = NULL;
-        if (PyList_Append(frame_info, frame) == -1) {
+        // This frame kicked off the current GC collection:
-            Py_DECREF(frame);
+        if (unwinder->gc && frame_addr == gc_frame) {
-            set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to append frame to frame info list");
+            _Py_DECLARE_STR(gc, "<GC>");
-            return -1;
+            extra_frame = &_Py_STR(gc);
+        }
+        // Otherwise, check for native frames to insert:
+        else if (unwinder->native &&
+                 // We've reached an interpreter trampoline frame:
+                 frame == NULL &&
+                 // Bottommost frame is always native, so skip that one:
+                 next_frame_addr &&
+                 // Only suppress native frames if GC tracking is enabled and the next frame will be a GC frame:
+                 !(unwinder->gc && next_frame_addr == gc_frame))
+        {
+            _Py_DECLARE_STR(native, "<native>");
+            extra_frame = &_Py_STR(native);
+        }
+        if (extra_frame) {
+            // Use "~" as file and 0 as line, since that's what pstats uses:
+            PyObject *extra_frame_info = make_frame_info(
+                unwinder, _Py_LATIN1_CHR('~'), _PyLong_GetZero(), extra_frame);
+            if (extra_frame_info == NULL) {
+                return -1;
+            }
+            int error = PyList_Append(frame_info, extra_frame_info);
+            Py_DECREF(extra_frame_info);
+            if (error) {
+                const char *e = "Failed to append extra frame to frame info list";
+                set_exception_cause(unwinder, PyExc_RuntimeError, e);
+                return -1;
+            }
+        }
+        if (frame) {
+            if (prev_frame_addr && frame_addr != prev_frame_addr) {
+                const char *f = "Broken frame chain: expected frame at 0x%lx, got 0x%lx";
+                PyErr_Format(PyExc_RuntimeError, f, prev_frame_addr, frame_addr);
+                Py_DECREF(frame);
+                const char *e = "Frame chain consistency check failed";
+                set_exception_cause(unwinder, PyExc_RuntimeError, e);
+                return -1;
+            }
+
+            if (PyList_Append(frame_info, frame) == -1) {
+                Py_DECREF(frame);
+                const char *e = "Failed to append frame to frame info list";
+                set_exception_cause(unwinder, PyExc_RuntimeError, e);
+                return -1;
+            }
+            Py_DECREF(frame);
         }
-        Py_DECREF(frame);
 
         prev_frame_addr = next_frame_addr;
         frame_addr = next_frame_addr;
@@ -2644,7 +2697,8 @@ static PyObject*
 unwind_stack_for_thread(
     RemoteUnwinderObject *unwinder,
     uintptr_t *current_tstate,
-    uintptr_t gil_holder_tstate
+    uintptr_t gil_holder_tstate,
+    uintptr_t gc_frame
 ) {
     PyObject *frame_info = NULL;
     PyObject *thread_id = NULL;
@@ -2746,7 +2800,7 @@ unwind_stack_for_thread(
         goto error;
     }
 
-    if (process_frame_chain(unwinder, frame_addr, &chunks, frame_info) < 0) {
+    if (process_frame_chain(unwinder, frame_addr, &chunks, frame_info, gc_frame) < 0) {
         set_exception_cause(unwinder, PyExc_RuntimeError, "Failed to process frame chain");
         goto error;
     }
@@ -2818,6 +2872,8 @@ _remote_debugging.RemoteUnwinder.__init__
     mode: int = 0
     debug: bool = False
     skip_non_matching_threads: bool = True
+    native: bool = False
+    gc: bool = False
 
 Initialize a new RemoteUnwinder object for debugging a remote Python process.
 
@@ -2832,6 +2888,10 @@ Initialize a new RemoteUnwinder object for debugging a remote Python process.
            lead to the exception.
     skip_non_matching_threads: If True, skip threads that don't match the selected mode.
                               If False, include all threads regardless of mode.
+    native: If True, include artificial "<native>" frames to denote calls to
+            non-Python code.
+    gc: If True, include artificial "<GC>" frames to denote active garbage
+        collection.
 
 The RemoteUnwinder provides functionality to inspect and debug a running Python
 process, including examining thread states, stack frames and other runtime data.
@@ -2848,8 +2908,9 @@ _remote_debugging_RemoteUnwinder___init___impl(RemoteUnwinderObject *self,
                                                int pid, int all_threads,
                                                int only_active_thread,
                                                int mode, int debug,
-                                               int skip_non_matching_threads)
+                                               int skip_non_matching_threads,
-/*[clinic end generated code: output=abf5ea5cd58bcb36 input=08fb6ace023ec3b5]*/
+                                               int native, int gc)
+/*[clinic end generated code: output=e9eb6b4df119f6e0 input=606d099059207df2]*/
 {
     // Validate that all_threads and only_active_thread are not both True
     if (all_threads && only_active_thread) {
@@ -2866,6 +2927,8 @@ _remote_debugging_RemoteUnwinder___init___impl(RemoteUnwinderObject *self,
     }
 #endif
 
+    self->native = native;
+    self->gc = gc;
     self->debug = debug;
     self->only_active_thread = only_active_thread;
     self->mode = mode;
@@ -3026,6 +3089,13 @@ _remote_debugging_RemoteUnwinder_get_stack_trace_impl(RemoteUnwinderObject *self
             goto exit;
         }
 
+        uintptr_t gc_frame = 0;
+        if (self->gc) {
+            gc_frame = GET_MEMBER(uintptr_t, interp_state_buffer,
+                                  self->debug_offsets.interpreter_state.gc
+                                  + self->debug_offsets.gc.frame);
+        }
+
         int64_t interpreter_id = GET_MEMBER(int64_t, interp_state_buffer,
                 self->debug_offsets.interpreter_state.id);
 
@@ -3085,7 +3155,9 @@ _remote_debugging_RemoteUnwinder_get_stack_trace_impl(RemoteUnwinderObject *self
         }
 
         while (current_tstate != 0) {
-            PyObject* frame_info = unwind_stack_for_thread(self, &current_tstate, gil_holder_tstate);
+            PyObject* frame_info = unwind_stack_for_thread(self, &current_tstate,
+                                                           gil_holder_tstate,
+                                                           gc_frame);
             if (!frame_info) {
                 // Check if this was an intentional skip due to mode-based filtering
                 if ((self->mode == PROFILING_MODE_CPU || self->mode == PROFILING_MODE_GIL) && !PyErr_Occurred()) {

Modules/clinic/_remote_debugging_module.c.h

@@ -11,7 +11,8 @@ preserve
 
 PyDoc_STRVAR(_remote_debugging_RemoteUnwinder___init____doc__,
 "RemoteUnwinder(pid, *, all_threads=False, only_active_thread=False,\n"
-"               mode=0, debug=False, skip_non_matching_threads=True)\n"
+"               mode=0, debug=False, skip_non_matching_threads=True,\n"
+"               native=False, gc=False)\n"
 "--\n"
 "\n"
 "Initialize a new RemoteUnwinder object for debugging a remote Python process.\n"
@@ -27,6 +28,10 @@ PyDoc_STRVAR(_remote_debugging_RemoteUnwinder___init____doc__,
 "           lead to the exception.\n"
 "    skip_non_matching_threads: If True, skip threads that don\'t match the selected mode.\n"
 "                              If False, include all threads regardless of mode.\n"
+"    native: If True, include artificial \"<native>\" frames to denote calls to\n"
+"            non-Python code.\n"
+"    gc: If True, include artificial \"<GC>\" frames to denote active garbage\n"
+"        collection.\n"
 "\n"
 "The RemoteUnwinder provides functionality to inspect and debug a running Python\n"
 "process, including examining thread states, stack frames and other runtime data.\n"
@@ -42,7 +47,8 @@ _remote_debugging_RemoteUnwinder___init___impl(RemoteUnwinderObject *self,
                                                int pid, int all_threads,
                                                int only_active_thread,
                                                int mode, int debug,
-                                               int skip_non_matching_threads);
+                                               int skip_non_matching_threads,
+                                               int native, int gc);
 
 static int
 _remote_debugging_RemoteUnwinder___init__(PyObject *self, PyObject *args, PyObject *kwargs)
@@ -50,7 +56,7 @@ _remote_debugging_RemoteUnwinder___init__(PyObject *self, PyObject *args, PyObje
     int return_value = -1;
     #if defined(Py_BUILD_CORE) && !defined(Py_BUILD_CORE_MODULE)
 
-    #define NUM_KEYWORDS 6
+    #define NUM_KEYWORDS 8
     static struct {
         PyGC_Head _this_is_not_used;
         PyObject_VAR_HEAD
@@ -59,7 +65,7 @@ _remote_debugging_RemoteUnwinder___init__(PyObject *self, PyObject *args, PyObje
     } _kwtuple = {
         .ob_base = PyVarObject_HEAD_INIT(&PyTuple_Type, NUM_KEYWORDS)
         .ob_hash = -1,
-        .ob_item = { &_Py_ID(pid), &_Py_ID(all_threads), &_Py_ID(only_active_thread), &_Py_ID(mode), &_Py_ID(debug), &_Py_ID(skip_non_matching_threads), },
+        .ob_item = { &_Py_ID(pid), &_Py_ID(all_threads), &_Py_ID(only_active_thread), &_Py_ID(mode), &_Py_ID(debug), &_Py_ID(skip_non_matching_threads), &_Py_ID(native), &_Py_ID(gc), },
     };
     #undef NUM_KEYWORDS
     #define KWTUPLE (&_kwtuple.ob_base.ob_base)
@@ -68,14 +74,14 @@ _remote_debugging_RemoteUnwinder___init__(PyObject *self, PyObject *args, PyObje
     #  define KWTUPLE NULL
     #endif  // !Py_BUILD_CORE
 
-    static const char * const _keywords[] = {"pid", "all_threads", "only_active_thread", "mode", "debug", "skip_non_matching_threads", NULL};
+    static const char * const _keywords[] = {"pid", "all_threads", "only_active_thread", "mode", "debug", "skip_non_matching_threads", "native", "gc", NULL};
     static _PyArg_Parser _parser = {
         .keywords = _keywords,
         .fname = "RemoteUnwinder",
         .kwtuple = KWTUPLE,
     };
     #undef KWTUPLE
-    PyObject *argsbuf[6];
+    PyObject *argsbuf[8];
     PyObject * const *fastargs;
     Py_ssize_t nargs = PyTuple_GET_SIZE(args);
     Py_ssize_t noptargs = nargs + (kwargs ? PyDict_GET_SIZE(kwargs) : 0) - 1;
@@ -85,6 +91,8 @@ _remote_debugging_RemoteUnwinder___init__(PyObject *self, PyObject *args, PyObje
     int mode = 0;
     int debug = 0;
     int skip_non_matching_threads = 1;
+    int native = 0;
+    int gc = 0;
 
     fastargs = _PyArg_UnpackKeywords(_PyTuple_CAST(args)->ob_item, nargs, kwargs, NULL, &_parser,
             /*minpos*/ 1, /*maxpos*/ 1, /*minkw*/ 0, /*varpos*/ 0, argsbuf);
@@ -134,12 +142,30 @@ _remote_debugging_RemoteUnwinder___init__(PyObject *self, PyObject *args, PyObje
             goto skip_optional_kwonly;
         }
     }
-    skip_non_matching_threads = PyObject_IsTrue(fastargs[5]);
+    if (fastargs[5]) {
-    if (skip_non_matching_threads < 0) {
+        skip_non_matching_threads = PyObject_IsTrue(fastargs[5]);
+        if (skip_non_matching_threads < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    if (fastargs[6]) {
+        native = PyObject_IsTrue(fastargs[6]);
+        if (native < 0) {
+            goto exit;
+        }
+        if (!--noptargs) {
+            goto skip_optional_kwonly;
+        }
+    }
+    gc = PyObject_IsTrue(fastargs[7]);
+    if (gc < 0) {
         goto exit;
     }
 skip_optional_kwonly:
-    return_value = _remote_debugging_RemoteUnwinder___init___impl((RemoteUnwinderObject *)self, pid, all_threads, only_active_thread, mode, debug, skip_non_matching_threads);
+    return_value = _remote_debugging_RemoteUnwinder___init___impl((RemoteUnwinderObject *)self, pid, all_threads, only_active_thread, mode, debug, skip_non_matching_threads, native, gc);
 
 exit:
     return return_value;
@@ -321,4 +347,4 @@ _remote_debugging_RemoteUnwinder_get_async_stack_trace(PyObject *self, PyObject
 
     return return_value;
 }
-/*[clinic end generated code: output=2caefeddf7683d32 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=99fed5c94cf36881 input=a9049054013a1b77]*/

Python/gc.c

@@ -2074,6 +2074,7 @@ _PyGC_Collect(PyThreadState *tstate, int generation, _PyGC_Reason reason)
         // Don't start a garbage collection if one is already in progress.
         return 0;
     }
+    gcstate->frame = tstate->current_frame;
 
     struct gc_collection_stats stats = { 0 };
     if (reason != _Py_GC_REASON_SHUTDOWN) {
@@ -2119,6 +2120,7 @@ _PyGC_Collect(PyThreadState *tstate, int generation, _PyGC_Reason reason)
     }
 #endif
     validate_spaces(gcstate);
+    gcstate->frame = NULL;
     _Py_atomic_store_int(&gcstate->collecting, 0);
 
     if (gcstate->debug & _PyGC_DEBUG_STATS) {

Python/gc_free_threading.c

@@ -2359,6 +2359,7 @@ gc_collect_main(PyThreadState *tstate, int generation, _PyGC_Reason reason)
         _Py_atomic_store_int(&gcstate->collecting, 0);
         return 0;
     }
+    gcstate->frame = tstate->current_frame;
 
     assert(generation >= 0 && generation < NUM_GENERATIONS);
 
@@ -2447,6 +2448,7 @@ gc_collect_main(PyThreadState *tstate, int generation, _PyGC_Reason reason)
     }
 
     assert(!_PyErr_Occurred(tstate));
+    gcstate->frame = NULL;
     _Py_atomic_store_int(&gcstate->collecting, 0);
     return n + m;
 }