perf python: Clean up pylint warnings in treport.py

Clean up pylint warnings in treport.py so that it passes pylint without
warning suppression comments:
- Replace broad 'except Exception:' clauses (W0718:
  broad-exception-caught) with specific exception tuples.
- Pass both pid and sample_tid to session.find_thread() so guest and
  process threads are resolved accurately.
- Rename parameter 'args' to 'pos_args' in FlameGraph.__init__() to
  avoid shadowing the outer scope variable 'args' (W0621:
  redefined-outer-name).
- Clear session = None in a finally block after session.process_events()
  to break the C perf_session reference cycle before launching the TUI.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 9 insertions, 6 deletions

diff --git a/tools/perf/python/treport.py b/tools/perf/python/treport.py
index 786b852f471c..0921b428b1aa 100755
--- a/tools/perf/python/treport.py
+++ b/tools/perf/python/treport.py
@@ -91,9 +91,9 @@ class ProfileNode:
         pid = sample.sample_pid
         try:
             assert session
-            thread = session.find_thread(sample.sample_tid)
+            thread = session.find_thread(pid, sample.sample_tid)
             comm = (thread.comm() if thread else None) or f"unknown ({pid})"
-        except Exception:
+        except (OSError, ValueError, KeyError, RuntimeError, TypeError, AttributeError):
             comm = f"unknown ({pid})"
 
         period = sample.sample_period
@@ -412,9 +412,9 @@ class FlameGraph(ScrollView):
     }
     """
 
-    def __init__(self, root: ProfileNode, *args, **kwargs):
+    def __init__(self, root: ProfileNode, *pos_args, **kwargs):
         """Initialize the FlameGraph widget."""
-        super().__init__(*args, **kwargs)
+        super().__init__(*pos_args, **kwargs)
         self.root = root
         self.cursor = root
         self.selected = root
@@ -549,12 +549,15 @@ if __name__ == "__main__":
     profile = ProfileBuilder()
     try:
         session = perf.session(perf.data(input_file), sample=profile.process_event)
-    except Exception as e:
+    except (OSError, ValueError, RuntimeError) as e:
         print(f"Error opening session: {e}", file=sys.stderr)
         sys.exit(1)
 
     # profile.process_event is called for each perf event to build the profile.
-    session.process_events()
+    try:
+        session.process_events()
+    finally:
+        session = None
 
     # Visualize data.
     app = ReportApp(profile.root)