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/util/counts.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 71 insertions(+) create mode 100644 tools/perf/util/counts.c (limited to 'tools/perf/util/counts.c') diff --git a/tools/perf/util/counts.c b/tools/perf/util/counts.c new file mode 100644 index 000000000..11cd85b27 --- /dev/null +++ b/tools/perf/util/counts.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include "evsel.h" +#include "counts.h" +#include +#include + +struct perf_counts *perf_counts__new(int ncpus, int nthreads) +{ + struct perf_counts *counts = zalloc(sizeof(*counts)); + + if (counts) { + struct xyarray *values; + + values = xyarray__new(ncpus, nthreads, sizeof(struct perf_counts_values)); + if (!values) { + free(counts); + return NULL; + } + + counts->values = values; + + values = xyarray__new(ncpus, nthreads, sizeof(bool)); + if (!values) { + xyarray__delete(counts->values); + free(counts); + return NULL; + } + + counts->loaded = values; + } + + return counts; +} + +void perf_counts__delete(struct perf_counts *counts) +{ + if (counts) { + xyarray__delete(counts->loaded); + xyarray__delete(counts->values); + free(counts); + } +} + +void perf_counts__reset(struct perf_counts *counts) +{ + xyarray__reset(counts->loaded); + xyarray__reset(counts->values); +} + +void evsel__reset_counts(struct evsel *evsel) +{ + perf_counts__reset(evsel->counts); +} + +int evsel__alloc_counts(struct evsel *evsel) +{ + struct perf_cpu_map *cpus = evsel__cpus(evsel); + int nthreads = perf_thread_map__nr(evsel->core.threads); + + evsel->counts = perf_counts__new(perf_cpu_map__nr(cpus), nthreads); + return evsel->counts != NULL ? 0 : -ENOMEM; +} + +void evsel__free_counts(struct evsel *evsel) +{ + perf_counts__delete(evsel->counts); + evsel->counts = NULL; +} -- cgit v1.3.1