From 2b97956af60810cd382b86b9ce9aea421b889861 Mon Sep 17 00:00:00 2001 From: Nuoqi Gui Date: Fri, 4 Sep 2026 12:41:55 +0200 Subject: selftests/bpf: Test rhtab kptr cancellation semantics Resizable hash-map updates and deletions must not perform full special-field destruction in their caller context. In particular, a referenced kptr must remain attached to the allocation until the memory allocator destructor can release it safely. Add separate coverage for both affected paths. The update test stores a task kptr, replaces the ordinary value bytes with BPF_EXIST, and verifies that the kptr survived. The delete test removes an element and exchanges its kptr through the still-valid map-value pointer before the allocation is reclaimed. Both cases observe a NULL kptr when rhtab uses bpf_obj_free_fields(). They recover and release the reference after rhtab switches to cancellation semantics. Signed-off-by: Nuoqi Gui [ kkd: Split update and delete coverage and rewrote the commit log ] Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904104203.345917-5-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- tools/perf/python/counting.py | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) create mode 100755 tools/perf/python/counting.py (limited to 'tools/perf/python/counting.py') diff --git a/tools/perf/python/counting.py b/tools/perf/python/counting.py new file mode 100755 index 000000000..02121d2bb --- /dev/null +++ b/tools/perf/python/counting.py @@ -0,0 +1,36 @@ +#!/usr/bin/env python3 +# SPDX-License-Identifier: GPL-2.0 +# -*- python -*- +# -*- coding: utf-8 -*- + +import argparse +import perf + +def main(event: str): + evlist = perf.parse_events(event) + + for evsel in evlist: + evsel.read_format = perf.FORMAT_TOTAL_TIME_ENABLED | perf.FORMAT_TOTAL_TIME_RUNNING + + evlist.open() + evlist.enable() + + count = 100000 + while count > 0: + count -= 1 + + evlist.disable() + + for evsel in evlist: + for cpu in evsel.cpus(): + for thread in evsel.threads(): + counts = evsel.read(cpu, thread) + print(f"For {evsel} val: {counts.val} enable: {counts.ena} run: {counts.run}") + + evlist.close() + +if __name__ == '__main__': + ap = argparse.ArgumentParser() + ap.add_argument('-e', '--event', help="Events to open", default="cpu-clock,task-clock") + args = ap.parse_args() + main(args.event) -- cgit v1.3.1