From fb30159426439bfe9a1435c0555f67201198988c Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Mon, 21 Aug 2023 22:00:58 -0700 Subject: [PATCH] selftests/bpf: Add a failure test for bpf_kptr_xchg() with local kptr For a bpf_kptr_xchg() with local kptr, if the map value kptr type and allocated local obj type does not match, with the previous patch, the below verifier error message will be logged: R2 is of type but is expected Without the previous patch, the test will have unexpected success. Signed-off-by: Yonghong Song Acked-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20230822050058.2887354-1-yonghong.song@linux.dev Signed-off-by: Alexei Starovoitov --- .../selftests/bpf/prog_tests/local_kptr_stash.c | 10 +++- .../selftests/bpf/progs/local_kptr_stash_fail.c | 65 ++++++++++++++++++++++ 2 files changed, 74 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/progs/local_kptr_stash_fail.c diff --git a/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c index 76f1da8..158616c 100644 --- a/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c +++ b/tools/testing/selftests/bpf/prog_tests/local_kptr_stash.c @@ -5,6 +5,7 @@ #include #include "local_kptr_stash.skel.h" +#include "local_kptr_stash_fail.skel.h" static void test_local_kptr_stash_simple(void) { LIBBPF_OPTS(bpf_test_run_opts, opts, @@ -51,10 +52,17 @@ static void test_local_kptr_stash_unstash(void) local_kptr_stash__destroy(skel); } -void test_local_kptr_stash_success(void) +static void test_local_kptr_stash_fail(void) +{ + RUN_TESTS(local_kptr_stash_fail); +} + +void test_local_kptr_stash(void) { if (test__start_subtest("local_kptr_stash_simple")) test_local_kptr_stash_simple(); if (test__start_subtest("local_kptr_stash_unstash")) test_local_kptr_stash_unstash(); + if (test__start_subtest("local_kptr_stash_fail")) + test_local_kptr_stash_fail(); } diff --git a/tools/testing/selftests/bpf/progs/local_kptr_stash_fail.c b/tools/testing/selftests/bpf/progs/local_kptr_stash_fail.c new file mode 100644 index 0000000..5484d1e --- /dev/null +++ b/tools/testing/selftests/bpf/progs/local_kptr_stash_fail.c @@ -0,0 +1,65 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */ + +#include +#include +#include +#include +#include "../bpf_experimental.h" +#include "bpf_misc.h" + +struct node_data { + long key; + long data; + struct bpf_rb_node node; +}; + +struct map_value { + struct node_data __kptr *node; +}; + +struct node_data2 { + long key[4]; +}; + +/* This is necessary so that LLVM generates BTF for node_data struct + * If it's not included, a fwd reference for node_data will be generated but + * no struct. Example BTF of "node" field in map_value when not included: + * + * [10] PTR '(anon)' type_id=35 + * [34] FWD 'node_data' fwd_kind=struct + * [35] TYPE_TAG 'kptr_ref' type_id=34 + */ +struct node_data *just_here_because_btf_bug; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, struct map_value); + __uint(max_entries, 2); +} some_nodes SEC(".maps"); + +SEC("tc") +__failure __msg("invalid kptr access, R2 type=ptr_node_data2 expected=ptr_node_data") +long stash_rb_nodes(void *ctx) +{ + struct map_value *mapval; + struct node_data2 *res; + int idx = 0; + + mapval = bpf_map_lookup_elem(&some_nodes, &idx); + if (!mapval) + return 1; + + res = bpf_obj_new(typeof(*res)); + if (!res) + return 1; + res->key[0] = 40; + + res = bpf_kptr_xchg(&mapval->node, res); + if (res) + bpf_obj_drop(res); + return 0; +} + +char _license[] SEC("license") = "GPL"; -- 2.7.4