gh-143423: Fix free-threaded build detection in sampling profiler

Lib/profiling/sampling/sample.py

@@ -42,6 +42,7 @@ def _pause_threads(unwinder, blocking):
     LiveStatsCollector = None
 
 _FREE_THREADED_BUILD = sysconfig.get_config_var("Py_GIL_DISABLED") is not None
+
 # Minimum number of samples required before showing the TUI
 # If fewer samples are collected, we skip the TUI and just print a message
 MIN_SAMPLES_FOR_TUI = 200
@@ -64,19 +65,23 @@ def __init__(self, pid, sample_interval_usec, all_threads, *, mode=PROFILING_MOD
         self.realtime_stats = False
 
     def _new_unwinder(self, native, gc, opcodes, skip_non_matching_threads):
-        if _FREE_THREADED_BUILD:
-            unwinder = _remote_debugging.RemoteUnwinder(
-                self.pid, all_threads=self.all_threads, mode=self.mode, native=native, gc=gc,
-                opcodes=opcodes, skip_non_matching_threads=skip_non_matching_threads,
-                cache_frames=True, stats=self.collect_stats
-            )
+        kwargs = {}
+        if _FREE_THREADED_BUILD or self.all_threads:
+            kwargs['all_threads'] = self.all_threads
         else:
-            unwinder = _remote_debugging.RemoteUnwinder(
-                self.pid, only_active_thread=bool(self.all_threads), mode=self.mode, native=native, gc=gc,
-                opcodes=opcodes, skip_non_matching_threads=skip_non_matching_threads,
-                cache_frames=True, stats=self.collect_stats
-            )
-        return unwinder
+            kwargs['only_active_thread'] = bool(self.all_threads)
+
+        return _remote_debugging.RemoteUnwinder(
+            self.pid,
+            mode=self.mode,
+            native=native,
+            gc=gc,
+            opcodes=opcodes,
+            skip_non_matching_threads=skip_non_matching_threads,
+            cache_frames=True,
+            stats=self.collect_stats,
+            **kwargs
+        )
 
     def sample(self, collector, duration_sec=None, *, async_aware=False):
         sample_interval_sec = self.sample_interval_usec / 1_000_000

Misc/NEWS.d/next/Library/2026-01-05-05-31-05.gh-issue-143423.X7YdnR.rst

@@ -0,0 +1 @@
+Fix free-threaded build detection in the sampling profiler when Py_GIL_DISABLED is set to 0.