Re: [PATCH 1/1] perf build: Require at least clang 16.0.6 to build BPF skeletons

[James Clark]

On 11/09/2024 13:24, Arnaldo Carvalho de Melo wrote:
> Howard reported problems using perf features that use BPF:
>
>    perf $ clang -v
>    Debian clang version 15.0.6
>    Target: x86_64-pc-linux-gnu
>    Thread model: posix
>    InstalledDir: /bin
>    Found candidate GCC installation: /bin/../lib/gcc/x86_64-linux-gnu/12
>    Selected GCC installation: /bin/../lib/gcc/x86_64-linux-gnu/12
>    Candidate multilib: .;@m64
>    Selected multilib: .;@m64
>    perf $ ./perf trace -e write --max-events=1
>    libbpf: prog 'sys_enter_rename': BPF program load failed: Permission denied
>    libbpf: prog 'sys_enter_rename': -- BEGIN PROG LOAD LOG --
>    0: R1=ctx() R10=fp0
>
> But it works with:
>
>    perf $ clang -v
>    Debian clang version 16.0.6 (15~deb12u1)
>    Target: x86_64-pc-linux-gnu
>    Thread model: posix
>    InstalledDir: /bin
>    Found candidate GCC installation: /bin/../lib/gcc/x86_64-linux-gnu/12
>    Selected GCC installation: /bin/../lib/gcc/x86_64-linux-gnu/12
>    Candidate multilib: .;@m64
>    Selected multilib: .;@m64
>    perf $ ./perf trace -e write --max-events=1
>         0.000 ( 0.009 ms): gmain/1448 write(fd: 4, buf: \1\0\0\0\0\0\0\0, count: 8)                         = 8 (kworker/0:0-eve)
>    perf $
>
> So lets make that the required version, if you happen to have a slightly
> older version where this work, please report so that we can adjust the
> minimum required version.

I wasn't able to reproduce the issue with either of these versions. But 
I suppose it could be an issue with only 15.0.6.

$ clang -v
Ubuntu clang version 15.0.7
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/12
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/12
Candidate multilib: .;@m64
Selected multilib: .;@m64


Ubuntu clang version 14.0.0-1ubuntu1.1
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/11
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/12
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/12
Candidate multilib: .;@m64
Selected multilib: .;@m64