On Thu, Sep 7, 2023 at 12:14 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding selftest that puts kprobe.multi on bpf_fentry_test1 that
> calls bpf_kfunc_common_test kfunc which has 3 perf event kprobes
> and 1 kprobe.multi attached.
>
> Because fprobe (kprobe.multi attach layear) does not have strict
> recursion check the kprobe's bpf_prog_active check is hit for test2-5.
>
> Disabling this test for arm64, because there's no fprobe support yet.
>
> Acked-by: Hou Tao <houtao1@xxxxxxxxxx>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Reviewed-and-tested-by: Song Liu <song@xxxxxxxxxx>
With on nitpick below.
> ---
> tools/testing/selftests/bpf/DENYLIST.aarch64 | 1 +
> .../testing/selftests/bpf/prog_tests/missed.c | 51 +++++++++++++++++++
> .../bpf/progs/missed_kprobe_recursion.c | 48 +++++++++++++++++
> 3 files changed, 100 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/missed_kprobe_recursion.c
>
> diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64
> index 7f768d335698..3f2187c049db 100644
> --- a/tools/testing/selftests/bpf/DENYLIST.aarch64
> +++ b/tools/testing/selftests/bpf/DENYLIST.aarch64
> @@ -15,3 +15,4 @@ fexit_test/fexit_many_args # fexit_many_args:FAIL:fexit_ma
> fill_link_info/kprobe_multi_link_info # bpf_program__attach_kprobe_multi_opts unexpected error: -95
> fill_link_info/kretprobe_multi_link_info # bpf_program__attach_kprobe_multi_opts unexpected error: -95
> fill_link_info/kprobe_multi_invalid_ubuff # bpf_program__attach_kprobe_multi_opts unexpected error: -95
> +missed/kprobe_recursion # missed_kprobe_recursion__attach unexpected error: -95 (errno 95)
> diff --git a/tools/testing/selftests/bpf/prog_tests/missed.c b/tools/testing/selftests/bpf/prog_tests/missed.c
> index fc674258c81f..f10dc9232b3f 100644
> --- a/tools/testing/selftests/bpf/prog_tests/missed.c
> +++ b/tools/testing/selftests/bpf/prog_tests/missed.c
> @@ -1,6 +1,7 @@
> // SPDX-License-Identifier: GPL-2.0
> #include <test_progs.h>
> #include "missed_kprobe.skel.h"
> +#include "missed_kprobe_recursion.skel.h"
>
> /*
> * Putting kprobe on bpf_fentry_test1 that calls bpf_kfunc_common_test
> @@ -40,8 +41,58 @@ static void test_missed_perf_kprobe(void)
> missed_kprobe__destroy(skel);
> }
>
> +static __u64 get_count(int fd)
nit: Probably rename it as get_missed_count() or get_missed().
> +{
> + struct bpf_prog_info info = {};
> + __u32 len = sizeof(info);
> + int err;
> +
> + err = bpf_prog_get_info_by_fd(fd, &info, &len);
> + if (!ASSERT_OK(err, "bpf_prog_get_info_by_fd"))
> + return (__u64) -1;
> + return info.recursion_misses;
> +}
[...]
