Verify the fact that only one fentry prog could be attached to another fentry, building up an attachment chain of limited size. Use existing bpf_testmod as a start of the chain. Signed-off-by: Dmitrii Dolgov <9erthalion6@xxxxxxxxx> --- Changes in v5: - Test only one level of attachment .../bpf/prog_tests/recursive_attach.c | 69 +++++++++++++++++++ .../selftests/bpf/progs/fentry_recursive.c | 19 +++++ .../bpf/progs/fentry_recursive_target.c | 20 ++++++ 3 files changed, 108 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/recursive_attach.c create mode 100644 tools/testing/selftests/bpf/progs/fentry_recursive.c create mode 100644 tools/testing/selftests/bpf/progs/fentry_recursive_target.c diff --git a/tools/testing/selftests/bpf/prog_tests/recursive_attach.c b/tools/testing/selftests/bpf/prog_tests/recursive_attach.c new file mode 100644 index 000000000000..7248d0661ee9 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/recursive_attach.c @@ -0,0 +1,69 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Red Hat, Inc. */ +#include <test_progs.h> +#include "fentry_recursive.skel.h" +#include "fentry_recursive_target.skel.h" +#include <bpf/btf.h> +#include "bpf/libbpf_internal.h" + +/* + * Test following scenarios: + * - attach one fentry progs to another one + * - more than one nesting levels are not allowed + */ +void test_recursive_fentry_attach(void) +{ + struct fentry_recursive_target *target_skel = NULL; + struct fentry_recursive *tracing_chain[2] = {}; + struct bpf_program *prog; + int prev_fd, err; + + target_skel = fentry_recursive_target__open_and_load(); + if (!ASSERT_OK_PTR(target_skel, "fentry_recursive_target__open_and_load")) + goto close_prog; + + /* Create an attachment chain with two fentry progs */ + for (int i = 0; i < 2; i++) { + tracing_chain[i] = fentry_recursive__open(); + if (!ASSERT_OK_PTR(tracing_chain[i], "fentry_recursive__open")) + goto close_prog; + + /* + * The first prog in the chain is going to be attached to the target + * fentry program, the second one to the previous in the chain. + */ + if (i == 0) { + prog = tracing_chain[0]->progs.recursive_attach; + prev_fd = bpf_program__fd(target_skel->progs.test1); + err = bpf_program__set_attach_target(prog, prev_fd, "test1"); + } else { + prog = tracing_chain[i]->progs.recursive_attach; + prev_fd = bpf_program__fd(tracing_chain[i-1]->progs.recursive_attach); + err = bpf_program__set_attach_target(prog, prev_fd, "recursive_attach"); + } + + if (!ASSERT_OK(err, "bpf_program__set_attach_target")) + goto close_prog; + + err = fentry_recursive__load(tracing_chain[i]); + /* The first attach should succeed, the second fail */ + if (i == 0) { + if (!ASSERT_OK(err, "fentry_recursive__load")) + goto close_prog; + + err = fentry_recursive__attach(tracing_chain[i]); + if (!ASSERT_OK(err, "fentry_recursive__attach")) + goto close_prog; + } else { + if (!ASSERT_ERR(err, "fentry_recursive__load")) + goto close_prog; + } + } + +close_prog: + fentry_recursive_target__destroy(target_skel); + for (int i = 0; i < 2; i++) { + if (tracing_chain[i]) + fentry_recursive__destroy(tracing_chain[i]); + } +} diff --git a/tools/testing/selftests/bpf/progs/fentry_recursive.c b/tools/testing/selftests/bpf/progs/fentry_recursive.c new file mode 100644 index 000000000000..1df490230344 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_recursive.c @@ -0,0 +1,19 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Red Hat, Inc. */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +__u64 test1_result = 0; + +/* + * Dummy fentry bpf prog for testing fentry attachment chains + */ +SEC("fentry/XXX") +int BPF_PROG(recursive_attach, int a) +{ + test1_result = a == 1; + return 0; +} diff --git a/tools/testing/selftests/bpf/progs/fentry_recursive_target.c b/tools/testing/selftests/bpf/progs/fentry_recursive_target.c new file mode 100644 index 000000000000..b6fb8ebd598d --- /dev/null +++ b/tools/testing/selftests/bpf/progs/fentry_recursive_target.c @@ -0,0 +1,20 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2023 Red Hat, Inc. */ +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> +#include <bpf/bpf_tracing.h> + +char _license[] SEC("license") = "GPL"; + +__u64 test1_result = 0; + +/* + * Dummy fentry bpf prog for testing fentry attachment chains. It's going to be + * a start of the chain. + */ +SEC("fentry/bpf_testmod_fentry_test1") +int BPF_PROG(test1, int a) +{ + test1_result = a == 1; + return 0; +} -- 2.41.0