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From:   Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date:   Thu, 5 Nov 2020 20:16:44 -0800
Message-ID: <CAADnVQL_mP7HNz1n+=S7Tjk8f7efm3_w5+VQVptD2y7Wts_Mig@mail.gmail.com>
Subject: Re: [PATCH] compiler-clang: remove version check for BPF Tracing
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        stable <stable@vger.kernel.org>,
        Chen Yu <yu.chen.surf@gmail.com>,
        Jarkko Sakkinen <jarkko@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        Andrii Nakryiko <andrii@kernel.org>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@chromium.org>,
        Nathan Chancellor <natechancellor@gmail.com>,
        Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Marco Elver <elver@google.com>,
        Arvind Sankar <nivedita@alum.mit.edu>,
        Randy Dunlap <rdunlap@infradead.org>,
        Sami Tolvanen <samitolvanen@google.com>,
        Ingo Molnar <mingo@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Network Development <netdev@vger.kernel.org>,
        bpf <bpf@vger.kernel.org>,
        Clang-Built-Linux ML <clang-built-linux@googlegroups.com>
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On Wed, Nov 4, 2020 at 11:11 AM Nick Desaulniers
<ndesaulniers@google.com> wrote:
>
> bpftrace parses the kernel headers and uses Clang under the hood. Remove
> the version check when __BPF_TRACING__ is defined (as bpftrace does) so
> that this tool can continue to parse kernel headers, even with older
> clang sources.
>
> Cc: <stable@vger.kernel.org>
> Fixes: commit 1f7a44f63e6c ("compiler-clang: add build check for clang 10.0.1")
> Reported-by: Chen Yu <yu.chen.surf@gmail.com>
> Reported-by: Jarkko Sakkinen <jarkko@kernel.org>
> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com>
> ---
>  include/linux/compiler-clang.h | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/include/linux/compiler-clang.h b/include/linux/compiler-clang.h
> index dd7233c48bf3..98cff1b4b088 100644
> --- a/include/linux/compiler-clang.h
> +++ b/include/linux/compiler-clang.h
> @@ -8,8 +8,10 @@
>                      + __clang_patchlevel__)
>
>  #if CLANG_VERSION < 100001
> +#ifndef __BPF_TRACING__
>  # error Sorry, your version of Clang is too old - please use 10.0.1 or newer.
>  #endif
> +#endif

I can take it through the bpf tree if no one objects.