On Thu, Sep 7, 2023 at 12:14 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding test that puts kprobe on bpf_fentry_test1 that calls
> bpf_kfunc_common_test kfunc, which has also kprobe on.
>
> The latter won't get triggered due to kprobe recursion check
> and kprobe missed counter is incremented.
>
> Acked-by: Hou Tao <houtao1@xxxxxxxxxx>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> .../selftests/bpf/bpf_testmod/bpf_testmod.c | 5 ++
> .../bpf/bpf_testmod/bpf_testmod_kfunc.h | 2 +
> .../testing/selftests/bpf/prog_tests/missed.c | 47 +++++++++++++++++++
> .../selftests/bpf/progs/missed_kprobe.c | 30 ++++++++++++
> 4 files changed, 84 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/prog_tests/missed.c
> create mode 100644 tools/testing/selftests/bpf/progs/missed_kprobe.c
>
> diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> index cefc5dd72573..a5e246f7b202 100644
> --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> @@ -138,6 +138,10 @@ __bpf_kfunc void bpf_iter_testmod_seq_destroy(struct bpf_iter_testmod_seq *it)
> it->cnt = 0;
> }
>
> +__bpf_kfunc void bpf_kfunc_common_test(void)
> +{
> +}
> +
> struct bpf_testmod_btf_type_tag_1 {
> int a;
> };
> @@ -343,6 +347,7 @@ BTF_SET8_START(bpf_testmod_common_kfunc_ids)
> BTF_ID_FLAGS(func, bpf_iter_testmod_seq_new, KF_ITER_NEW)
> BTF_ID_FLAGS(func, bpf_iter_testmod_seq_next, KF_ITER_NEXT | KF_RET_NULL)
> BTF_ID_FLAGS(func, bpf_iter_testmod_seq_destroy, KF_ITER_DESTROY)
> +BTF_ID_FLAGS(func, bpf_kfunc_common_test)
> BTF_SET8_END(bpf_testmod_common_kfunc_ids)
>
> static const struct btf_kfunc_id_set bpf_testmod_common_kfunc_set = {
> diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
> index f5c5b1375c24..7c664dd61059 100644
> --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
> +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod_kfunc.h
> @@ -104,4 +104,6 @@ void bpf_kfunc_call_test_fail1(struct prog_test_fail1 *p);
> void bpf_kfunc_call_test_fail2(struct prog_test_fail2 *p);
> void bpf_kfunc_call_test_fail3(struct prog_test_fail3 *p);
> void bpf_kfunc_call_test_mem_len_fail1(void *mem, int len);
> +
> +void bpf_kfunc_common_test(void) __ksym;
> #endif /* _BPF_TESTMOD_KFUNC_H */
> diff --git a/tools/testing/selftests/bpf/prog_tests/missed.c b/tools/testing/selftests/bpf/prog_tests/missed.c
> new file mode 100644
> index 000000000000..fc674258c81f
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/missed.c
> @@ -0,0 +1,47 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <test_progs.h>
> +#include "missed_kprobe.skel.h"
> +
> +/*
> + * Putting kprobe on bpf_fentry_test1 that calls bpf_kfunc_common_test
> + * kfunc, which has also kprobe on. The latter won't get triggered due
> + * to kprobe recursion check and kprobe missed counter is incremented.
> + */
> +static void test_missed_perf_kprobe(void)
> +{
> + LIBBPF_OPTS(bpf_test_run_opts, topts);
> + struct bpf_link_info info = {};
> + struct missed_kprobe *skel;
> + __u32 len = sizeof(info);
> + int err, prog_fd;
> +
> + skel = missed_kprobe__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "missed_kprobe__open_and_load"))
> + goto cleanup;
> +
> + err = missed_kprobe__attach(skel);
> + if (!ASSERT_OK(err, "missed_kprobe__attach"))
> + goto cleanup;
> +
> + prog_fd = bpf_program__fd(skel->progs.trigger);
> + err = bpf_prog_test_run_opts(prog_fd, &topts);
> + ASSERT_OK(err, "test_run");
> + ASSERT_EQ(topts.retval, 0, "test_run");
> +
> + err = bpf_link_get_info_by_fd(bpf_link__fd(skel->links.test2), &info, &len);
> + if (!ASSERT_OK(err, "bpf_link_get_info_by_fd"))
> + goto cleanup;
> +
> + ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "info.type");
> + ASSERT_EQ(info.perf_event.type, BPF_PERF_EVENT_KPROBE, "info.perf_event.type");
> + ASSERT_EQ(info.perf_event.kprobe.missed, 1, "info.perf_event.kprobe.missed");
> +
> +cleanup:
> + missed_kprobe__destroy(skel);
> +}
> +
> +void serial_test_missed(void)
why serial? if you check for kprobe.missed >= 1, it should be fine
even if some other test calls this testmod kfunc, right?
> +{
> + if (test__start_subtest("perf_kprobe"))
> + test_missed_perf_kprobe();
> +}
> diff --git a/tools/testing/selftests/bpf/progs/missed_kprobe.c b/tools/testing/selftests/bpf/progs/missed_kprobe.c
> new file mode 100644
> index 000000000000..7f9ef701f5de
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/missed_kprobe.c
> @@ -0,0 +1,30 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "vmlinux.h"
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +#include "../bpf_testmod/bpf_testmod_kfunc.h"
> +
> +char _license[] SEC("license") = "GPL";
> +
> +/*
> + * No tests in here, just to trigger 'bpf_fentry_test*'
> + * through tracing test_run
> + */
> +SEC("fentry/bpf_modify_return_test")
> +int BPF_PROG(trigger)
> +{
> + return 0;
> +}
> +
> +SEC("kprobe/bpf_fentry_test1")
> +int test1(struct pt_regs *ctx)
> +{
> + bpf_kfunc_common_test();
> + return 0;
> +}
> +
> +SEC("kprobe/bpf_kfunc_common_test")
> +int test2(struct pt_regs *ctx)
> +{
> + return 0;
> +}
> --
> 2.41.0
>
