From: Jiri Olsa Date: Sat, 6 Jun 2026 12:39:54 +0000 (+0200) Subject: selftests/bpf: Add tracing multi attach rollback tests X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=b349efe49a123f032e54d7e894d708ea5daa10d2;p=thirdparty%2Flinux.git selftests/bpf: Add tracing multi attach rollback tests Adding tests for the rollback code when the tracing_multi link won't get attached, covering 2 reasons: - wrong btf id passed by user, where all previously allocated trampolines will be released - trampoline for requested function is fully attached (has already maximum programs attached) and the link fails, the rollback code needs to release all previously link-ed trampolines and release them We need the bpf_fentry_test* unattached for the tests to pass, so the rollback tests are serial. Signed-off-by: Jiri Olsa Link: https://lore.kernel.org/r/20260606123955.345967-30-jolsa@kernel.org Signed-off-by: Alexei Starovoitov --- diff --git a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c index cb39bf610823..f02ffc7f41d7 100644 --- a/tools/testing/selftests/bpf/prog_tests/tracing_multi.c +++ b/tools/testing/selftests/bpf/prog_tests/tracing_multi.c @@ -11,6 +11,7 @@ #include "tracing_multi_fail.skel.h" #include "tracing_multi_verifier.skel.h" #include "tracing_multi_bench.skel.h" +#include "tracing_multi_rollback.skel.h" #include "trace_helpers.h" static __u64 bpf_fentry_test_cookies[] = { @@ -717,6 +718,217 @@ cleanup: btf__free(btf); } +static void tracing_multi_rollback_run(struct tracing_multi_rollback *skel) +{ + LIBBPF_OPTS(bpf_test_run_opts, topts); + int err, prog_fd; + + prog_fd = bpf_program__fd(skel->progs.test_fentry); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run"); + + /* make sure the rollback code did not leave any program attached */ + ASSERT_EQ(skel->bss->test_result_fentry, 0, "test_result_fentry"); + ASSERT_EQ(skel->bss->test_result_fexit, 0, "test_result_fexit"); +} + +static void test_rollback_put(void) +{ + LIBBPF_OPTS(bpf_tracing_multi_opts, opts); + struct tracing_multi_rollback *skel = NULL; + size_t cnt = FUNCS_CNT; + __u32 *ids = NULL; + int err; + + skel = tracing_multi_rollback__open(); + if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open")) + return; + + bpf_program__set_autoload(skel->progs.test_fentry, true); + bpf_program__set_autoload(skel->progs.test_fexit, true); + + err = tracing_multi_rollback__load(skel); + if (!ASSERT_OK(err, "tracing_multi_rollback__load")) + goto cleanup; + + ids = get_ids(bpf_fentry_test, cnt, NULL); + if (!ASSERT_OK_PTR(ids, "get_ids")) + goto cleanup; + + /* + * Mangle last id to trigger rollback, which needs to do put + * on get-ed trampolines. + */ + ids[9] = 0; + + opts.ids = ids; + opts.cnt = cnt; + + skel->bss->pid = getpid(); + + skel->links.test_fentry = bpf_program__attach_tracing_multi(skel->progs.test_fentry, + NULL, &opts); + if (!ASSERT_ERR_PTR(skel->links.test_fentry, "bpf_program__attach_tracing_multi")) + goto cleanup; + + skel->links.test_fexit = bpf_program__attach_tracing_multi(skel->progs.test_fexit, + NULL, &opts); + if (!ASSERT_ERR_PTR(skel->links.test_fexit, "bpf_program__attach_tracing_multi")) + goto cleanup; + + /* We don't really attach any program, but let's make sure. */ + tracing_multi_rollback_run(skel); + +cleanup: + tracing_multi_rollback__destroy(skel); + free(ids); +} + +static void fillers_cleanup(struct tracing_multi_rollback **skels, int cnt) +{ + int i; + + for (i = 0; i < cnt; i++) + tracing_multi_rollback__destroy(skels[i]); + + free(skels); +} + +static struct tracing_multi_rollback *extra_load_and_link(void) +{ + struct tracing_multi_rollback *skel; + int err; + + skel = tracing_multi_rollback__open(); + if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open")) + goto cleanup; + + bpf_program__set_autoload(skel->progs.extra, true); + + err = tracing_multi_rollback__load(skel); + if (!ASSERT_OK(err, "tracing_multi_rollback__load")) + goto cleanup; + + skel->links.extra = bpf_program__attach_trace(skel->progs.extra); + if (!ASSERT_OK_PTR(skel->links.extra, "bpf_program__attach_trace")) + goto cleanup; + + return skel; + +cleanup: + tracing_multi_rollback__destroy(skel); + return NULL; +} + +static struct tracing_multi_rollback **fillers_load_and_link(int max) +{ + struct tracing_multi_rollback **skels, *skel; + int i, err; + + skels = calloc(max + 1, sizeof(*skels)); + if (!ASSERT_OK_PTR(skels, "calloc")) + return NULL; + + for (i = 0; i < max; i++) { + skel = skels[i] = tracing_multi_rollback__open(); + if (!ASSERT_OK_PTR(skels[i], "tracing_multi_rollback__open")) + goto cleanup; + + bpf_program__set_autoload(skel->progs.filler, true); + + err = tracing_multi_rollback__load(skel); + if (!ASSERT_OK(err, "tracing_multi_rollback__load")) + goto cleanup; + + skel->links.filler = bpf_program__attach_trace(skel->progs.filler); + if (!ASSERT_OK_PTR(skels[i]->links.filler, "bpf_program__attach_trace")) + goto cleanup; + } + + return skels; + +cleanup: + fillers_cleanup(skels, i + 1); + return NULL; +} + +static void test_rollback_unlink(void) +{ + struct tracing_multi_rollback *skel = NULL, *extra; + LIBBPF_OPTS(bpf_tracing_multi_opts, opts); + struct tracing_multi_rollback **fillers; + size_t cnt = FUNCS_CNT; + __u32 *ids = NULL; + int err, max; + + max = get_bpf_max_tramp_links(); + if (!ASSERT_GE(max, 1, "bpf_max_tramp_links")) + return; + + /* Attach maximum allowed programs to bpf_fentry_test10 */ + fillers = fillers_load_and_link(max); + if (!ASSERT_OK_PTR(fillers, "fillers_load_and_link")) + return; + + extra = extra_load_and_link(); + if (!ASSERT_OK_PTR(extra, "extra_load_and_link")) + goto cleanup; + + skel = tracing_multi_rollback__open(); + if (!ASSERT_OK_PTR(skel, "tracing_multi_rollback__open")) + goto cleanup; + + bpf_program__set_autoload(skel->progs.test_fentry, true); + bpf_program__set_autoload(skel->progs.test_fexit, true); + + /* + * Attach tracing_multi link on bpf_fentry_test1-10, which will + * fail on bpf_fentry_test10 function, because it already has + * maximum allowed programs attached. + * + * The rollback needs to unlink already link-ed trampolines and + * put all of them. + */ + err = tracing_multi_rollback__load(skel); + if (!ASSERT_OK(err, "tracing_multi_rollback__load")) + goto cleanup; + + ids = get_ids(bpf_fentry_test, cnt, NULL); + if (!ASSERT_OK_PTR(ids, "get_ids")) + goto cleanup; + + opts.ids = ids; + opts.cnt = cnt; + + skel->bss->pid = getpid(); + + skel->links.test_fentry = bpf_program__attach_tracing_multi(skel->progs.test_fentry, + NULL, &opts); + if (!ASSERT_ERR_PTR(skel->links.test_fentry, "bpf_program__attach_tracing_multi")) + goto cleanup; + + skel->links.test_fexit = bpf_program__attach_tracing_multi(skel->progs.test_fexit, + NULL, &opts); + if (!ASSERT_ERR_PTR(skel->links.test_fexit, "bpf_program__attach_tracing_multi")) + goto cleanup; + + tracing_multi_rollback_run(skel); + +cleanup: + fillers_cleanup(fillers, max); + tracing_multi_rollback__destroy(extra); + tracing_multi_rollback__destroy(skel); + free(ids); +} + +void serial_test_tracing_multi_attach_rollback(void) +{ + if (test__start_subtest("put")) + test_rollback_put(); + if (test__start_subtest("unlink")) + test_rollback_unlink(); +} + void test_tracing_multi_test(void) { #ifndef __x86_64__ diff --git a/tools/testing/selftests/bpf/progs/tracing_multi_rollback.c b/tools/testing/selftests/bpf/progs/tracing_multi_rollback.c new file mode 100644 index 000000000000..a49d1d841f3a --- /dev/null +++ b/tools/testing/selftests/bpf/progs/tracing_multi_rollback.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include + +char _license[] SEC("license") = "GPL"; + +int pid = 0; + +__u64 test_result_fentry = 0; +__u64 test_result_fexit = 0; + +SEC("?fentry.multi") +int BPF_PROG(test_fentry) +{ + if (bpf_get_current_pid_tgid() >> 32 != pid) + return 0; + + test_result_fentry++; + return 0; +} + +SEC("?fexit.multi") +int BPF_PROG(test_fexit) +{ + if (bpf_get_current_pid_tgid() >> 32 != pid) + return 0; + + test_result_fexit++; + return 0; +} + +SEC("?fentry/bpf_fentry_test1") +int BPF_PROG(extra) +{ + return 0; +} + +SEC("?fentry/bpf_fentry_test10") +int BPF_PROG(filler) +{ + return 0; +}