linux-kernel - Re: [PATCH v1 1/4] perf parse-events: Remove BPF event support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZTLlfXM4MhW1GEIJ@kernel.org>
Date:   Fri, 20 Oct 2023 17:39:25 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Manu Bretelle <chantr4@...il.com>
Cc:     Ian Rogers <irogers@...gle.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Nathan Chancellor <nathan@...nel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, Fangrui Song <maskray@...gle.com>,
        Anshuman Khandual <anshuman.khandual@....com>,
        Andi Kleen <ak@...ux.intel.com>, Leo Yan <leo.yan@...aro.org>,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Carsten Haitzler <carsten.haitzler@....com>,
        Ravi Bangoria <ravi.bangoria@....com>,
        "Naveen N. Rao" <naveen.n.rao@...ux.vnet.ibm.com>,
        Athira Rajeev <atrajeev@...ux.vnet.ibm.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Yang Jihong <yangjihong1@...wei.com>,
        James Clark <james.clark@....com>,
        Tiezhu Yang <yangtiezhu@...ngson.cn>,
        Eduard Zingerman <eddyz87@...il.com>,
        Andrii Nakryiko <andrii@...nel.org>,
        Yonghong Song <yhs@...com>, Rob Herring <robh@...nel.org>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        bpf@...r.kernel.org, llvm@...ts.linux.dev,
        Wang Nan <wangnan0@...wei.com>,
        Wang ShaoBo <bobo.shaobowang@...wei.com>,
        YueHaibing <yuehaibing@...wei.com>,
        He Kuang <hekuang@...wei.com>,
        Brendan Gregg <brendan.d.gregg@...il.com>,
        Quentin Monnet <quentin@...valent.com>
Subject: Re: [PATCH v1 1/4] perf parse-events: Remove BPF event support

Em Thu, Oct 19, 2023 at 03:48:56PM -0700, Manu Bretelle escreveu:
> On Thu, Oct 19, 2023 at 06:08:33PM -0300, Arnaldo Carvalho de Melo wrote:
> > I wonder how to improve the current situation to detect these kinds of
> > problems in the future, i.e. how to notice that some file needed by some
> > Makefile, etc got removed or that some feature test fails because some
> > change in the test .c files makes them fail and thus activates fallbacks
> > like the one above :-\
 
> I think it is tricky. Specifically to this situation, some CI could try to build
> the different combinaison of bpftool and check the features through the build
> `bpftool --version`.

Right, if the right packages are installed, we expect to get some
bpftool build output, if that changes after some patch, flag it.

Does bpftool have something like:

⬢[acme@...lbox perf-tools-next]$ perf version --build-options
perf version 6.6.rc1.ga8dd62d05e56
                 dwarf: [ on  ]  # HAVE_DWARF_SUPPORT
    dwarf_getlocations: [ on  ]  # HAVE_DWARF_GETLOCATIONS_SUPPORT
         syscall_table: [ on  ]  # HAVE_SYSCALL_TABLE_SUPPORT
                libbfd: [ OFF ]  # HAVE_LIBBFD_SUPPORT
            debuginfod: [ on  ]  # HAVE_DEBUGINFOD_SUPPORT
                libelf: [ on  ]  # HAVE_LIBELF_SUPPORT
               libnuma: [ on  ]  # HAVE_LIBNUMA_SUPPORT
numa_num_possible_cpus: [ on  ]  # HAVE_LIBNUMA_SUPPORT
               libperl: [ on  ]  # HAVE_LIBPERL_SUPPORT
             libpython: [ on  ]  # HAVE_LIBPYTHON_SUPPORT
              libslang: [ on  ]  # HAVE_SLANG_SUPPORT
             libcrypto: [ on  ]  # HAVE_LIBCRYPTO_SUPPORT
             libunwind: [ on  ]  # HAVE_LIBUNWIND_SUPPORT
    libdw-dwarf-unwind: [ on  ]  # HAVE_DWARF_SUPPORT
                  zlib: [ on  ]  # HAVE_ZLIB_SUPPORT
                  lzma: [ on  ]  # HAVE_LZMA_SUPPORT
             get_cpuid: [ on  ]  # HAVE_AUXTRACE_SUPPORT
                   bpf: [ on  ]  # HAVE_LIBBPF_SUPPORT
                   aio: [ on  ]  # HAVE_AIO_SUPPORT
                  zstd: [ on  ]  # HAVE_ZSTD_SUPPORT
               libpfm4: [ on  ]  # HAVE_LIBPFM
         libtraceevent: [ on  ]  # HAVE_LIBTRACEEVENT
         bpf_skeletons: [ on  ]  # HAVE_BPF_SKEL
⬢[acme@...lbox perf-tools-next]$

?

> This is actually a test that I run internally to make sure our build has some
> feature enabled.
> This is actually tested by bpftool in the GH CI:
> https://github.com/libbpf/bpftool/blob/main/.github/workflows/build.yaml#L62
 
> As a matter of fact, it would not have been detected because that CI uses a
> different Makefile.feature.
 
> Quentin and I were talking offline how we could improve bpftool CI at diff time.
> This is an example where it would have helped :)
> 
> > I'll get this merged in my perf-tools-fixes-for-v6.6 that I'll submit
> > tomorrow to Linus, thanks for reporting!
> > 
> > I'll add your:
> > 
> > Reported-by: Manu Bretelle <chantr4@...il.com>
> > 
> > And:
> > 
> > Fixes: 56b11a2126bf2f42 ("perf bpf: Remove support for embedding clang for compiling BPF events (-e foo.c)")
> > 
> > Ok?
 
> SGTM. Thanks for the quick turnaround.
 
> Reviewed-by: Manu Bretelle <chantr4@...il.com>

You're welcome, thanks for the detailed report, the patch was just sent
to Linus.

- Arnaldo