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From:   Andrii Nakryiko <andrii.nakryiko@gmail.com>
Date:   Wed, 18 May 2022 16:50:58 -0700
Message-ID: <CAEf4BzYNa0F21ydMLvmeGZWzvO_o5Fh0Af0zwWGNxMh6emQTSg@mail.gmail.com>
Subject: Re: [PATCH bpf-next v3 4/4] bpf_trace: pass array of u64 values in kprobe_multi.addrs
To:     Eugene Syromiatnikov <esyr@redhat.com>
Cc:     Jiri Olsa <jolsa@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Shuah Khan <shuah@kernel.org>,
        "open list:KERNEL SELFTEST FRAMEWORK" 
        <linux-kselftest@vger.kernel.org>
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On Tue, May 17, 2022 at 12:37 AM Eugene Syromiatnikov <esyr@redhat.com> wrote:
>
> With the interface as defined, it is impossible to pass 64-bit kernel
> addresses from a 32-bit userspace process in BPF_LINK_TYPE_KPROBE_MULTI,
> which severly limits the useability of the interface, change the ABI
> to accept an array of u64 values instead of (kernel? user?) longs.
> Interestingly, the rest of the libbpf infrastructure uses 64-bit values
> for kallsyms addresses already, so this patch also eliminates
> the sym_addr cast in tools/lib/bpf/libbpf.c:resolve_kprobe_multi_cb().
>
> Fixes: 0dcac272540613d4 ("bpf: Add multi kprobe link")
> Fixes: 5117c26e877352bc ("libbpf: Add bpf_link_create support for multi kprobes")
> Fixes: ddc6b04989eb0993 ("libbpf: Add bpf_program__attach_kprobe_multi_opts function")
> Fixes: f7a11eeccb111854 ("selftests/bpf: Add kprobe_multi attach test")
> Fixes: 9271a0c7ae7a9147 ("selftests/bpf: Add attach test for bpf_program__attach_kprobe_multi_opts")
> Fixes: 2c6401c966ae1fbe ("selftests/bpf: Add kprobe_multi bpf_cookie test")
> Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
> ---
>  kernel/trace/bpf_trace.c                           | 25 ++++++++++++++++++----

kernel changes should go into a separate patch (and seems like they
logically fit together with patch #3, no?)

>  tools/lib/bpf/bpf.h                                |  2 +-
>  tools/lib/bpf/libbpf.c                             |  8 +++----
>  tools/lib/bpf/libbpf.h                             |  2 +-
>  .../testing/selftests/bpf/prog_tests/bpf_cookie.c  |  2 +-
>  .../selftests/bpf/prog_tests/kprobe_multi_test.c   |  8 +++----
>  6 files changed, 32 insertions(+), 15 deletions(-)
>

[...]