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/tests/evsel-roundtrip-name.c | 104 ++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+) create mode 100644 tools/perf/tests/evsel-roundtrip-name.c (limited to 'tools/perf/tests/evsel-roundtrip-name.c') diff --git a/tools/perf/tests/evsel-roundtrip-name.c b/tools/perf/tests/evsel-roundtrip-name.c new file mode 100644 index 000000000..1922cac13 --- /dev/null +++ b/tools/perf/tests/evsel-roundtrip-name.c @@ -0,0 +1,104 @@ +// SPDX-License-Identifier: GPL-2.0 +#include "evlist.h" +#include "evsel.h" +#include "parse-events.h" +#include "tests.h" +#include "debug.h" +#include + +static int perf_evsel__roundtrip_cache_name_test(void) +{ + int ret = TEST_OK; + + for (int type = 0; type < PERF_COUNT_HW_CACHE_MAX; type++) { + for (int op = 0; op < PERF_COUNT_HW_CACHE_OP_MAX; op++) { + /* skip invalid cache type */ + if (!evsel__is_cache_op_valid(type, op)) + continue; + + for (int res = 0; res < PERF_COUNT_HW_CACHE_RESULT_MAX; res++) { + char name[128]; + struct evlist *evlist = evlist__new(); + struct evsel *evsel; + int err; + + if (evlist == NULL) { + pr_debug("Failed to alloc evlist"); + return TEST_FAIL; + } + __evsel__hw_cache_type_op_res_name(type, op, res, + name, sizeof(name)); + + err = parse_event(evlist, name); + if (err) { + pr_debug("Failure to parse cache event '%s' possibly as PMUs don't support it", + name); + evlist__delete(evlist); + continue; + } + evlist__for_each_entry(evlist, evsel) { + if (!evsel__name_is(evsel, name)) { + pr_debug("%s != %s\n", evsel__name(evsel), name); + ret = TEST_FAIL; + } + } + evlist__delete(evlist); + } + } + } + return ret; +} + +static int perf_evsel__name_array_test(const char *const names[], int nr_names) +{ + int ret = TEST_OK; + + for (int i = 0; i < nr_names; ++i) { + struct evlist *evlist = evlist__new(); + struct evsel *evsel; + int err; + + if (evlist == NULL) { + pr_debug("Failed to alloc evlist"); + return TEST_FAIL; + } + err = parse_event(evlist, names[i]); + if (err) { + pr_debug("failed to parse event '%s', err %d\n", + names[i], err); + evlist__delete(evlist); + ret = TEST_FAIL; + continue; + } + evlist__for_each_entry(evlist, evsel) { + if (!evsel__name_is(evsel, names[i])) { + pr_debug("%s != %s\n", evsel__name(evsel), names[i]); + ret = TEST_FAIL; + } + } + evlist__delete(evlist); + } + return ret; +} + +static int test__perf_evsel__roundtrip_name_test(struct test_suite *test __maybe_unused, + int subtest __maybe_unused) +{ + int err = 0, ret = TEST_OK; + + err = perf_evsel__name_array_test(evsel__hw_names, PERF_COUNT_HW_MAX); + if (err) + ret = err; + + err = perf_evsel__name_array_test(evsel__sw_names, PERF_COUNT_SW_DUMMY + 1); + if (err) + ret = err; + + err = perf_evsel__roundtrip_cache_name_test(); + if (err) + ret = err; + + return ret; +} + +DEFINE_SUITE("Roundtrip evsel->name", perf_evsel__roundtrip_name_test); -- cgit v1.3.1