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/bitmap.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 56 insertions(+) create mode 100644 tools/perf/tests/bitmap.c (limited to 'tools/perf/tests/bitmap.c') diff --git a/tools/perf/tests/bitmap.c b/tools/perf/tests/bitmap.c new file mode 100644 index 000000000..e7adf60be --- /dev/null +++ b/tools/perf/tests/bitmap.c @@ -0,0 +1,56 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include "tests.h" +#include "debug.h" + +#define NBITS 100 + +static unsigned long *get_bitmap(const char *str, int nbits) +{ + struct perf_cpu_map *map = perf_cpu_map__new(str); + unsigned long *bm; + + bm = bitmap_zalloc(nbits); + + if (map && bm) { + unsigned int i; + struct perf_cpu cpu; + + perf_cpu_map__for_each_cpu(cpu, i, map) + __set_bit(cpu.cpu, bm); + } + + perf_cpu_map__put(map); + return bm; +} + +static int test_bitmap(const char *str) +{ + unsigned long *bm = get_bitmap(str, NBITS); + char buf[100]; + int ret; + + bitmap_scnprintf(bm, NBITS, buf, sizeof(buf)); + pr_debug("bitmap: %s\n", buf); + + ret = !strcmp(buf, str); + free(bm); + return ret; +} + +static int test__bitmap_print(struct test_suite *test __maybe_unused, int subtest __maybe_unused) +{ + TEST_ASSERT_VAL("failed to convert map", test_bitmap("1")); + TEST_ASSERT_VAL("failed to convert map", test_bitmap("1,5")); + TEST_ASSERT_VAL("failed to convert map", test_bitmap("1,3,5,7,9,11,13,15,17,19,21-40")); + TEST_ASSERT_VAL("failed to convert map", test_bitmap("2-5")); + TEST_ASSERT_VAL("failed to convert map", test_bitmap("1,3-6,8-10,24,35-37")); + TEST_ASSERT_VAL("failed to convert map", test_bitmap("1,3-6,8-10,24,35-37")); + TEST_ASSERT_VAL("failed to convert map", test_bitmap("1-10,12-20,22-30,32-40")); + return 0; +} + +DEFINE_SUITE("Print bitmap", bitmap_print); -- cgit v1.3.1