[PATCH net-next] selftests: net: py: handle interrupt during cleanup

[Jakub Kicinski <kuba@kernel.org>]

Following up on the old discussion [1]. Let the BaseExceptions out of
defer()'ed cleanup. And handle it in the main loop. This allows us to
exit the tests if user hit Ctrl-C during defer().

Link: https://lore.kernel.org/20251119063228.3adfd743@kernel.org # [1]
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
CC: shuah@kernel.org
CC: willemb@google.com
CC: petrm@nvidia.com
CC: linux-kselftest@vger.kernel.org
---
 tools/testing/selftests/net/lib/py/ksft.py | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/lib/py/ksft.py b/tools/testing/selftests/net/lib/py/ksft.py
index ebd82940ee50..531e7fa1b3ea 100644
--- a/tools/testing/selftests/net/lib/py/ksft.py
+++ b/tools/testing/selftests/net/lib/py/ksft.py
@@ -163,7 +163,7 @@ KSFT_DISRUPTIVE = True
         entry = global_defer_queue.pop()
         try:
             entry.exec_only()
-        except BaseException:
+        except Exception:
             ksft_pr(f"Exception while handling defer / cleanup (callback {i} of {qlen_start})!")
             tb = traceback.format_exc()
             for line in tb.strip().split('\n'):
@@ -333,7 +333,21 @@ KsftCaseFunction = namedtuple("KsftCaseFunction",
             KSFT_RESULT = False
             cnt_key = 'fail'
 
-        ksft_flush_defer()
+        try:
+            ksft_flush_defer()
+        except BaseException as e:
+            tb = traceback.format_exc()
+            for line in tb.strip().split('\n'):
+                ksft_pr("Exception|", line)
+            if isinstance(e, KeyboardInterrupt):
+                ksft_pr()
+                ksft_pr("WARN: defer() interrupted, cleanup may be incomplete.")
+                ksft_pr("      Attempting to finish cleanup before exiting.")
+                ksft_pr("      Interrupt again to exit immediately.")
+                ksft_pr()
+                stop = True
+            # Flush was interrupted, try to finish the job best we can
+            ksft_flush_defer()
 
         if not cnt_key:
             cnt_key = 'pass' if KSFT_RESULT else 'fail'
-- 
2.51.1