From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-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