Re: Flaky tests

[Namhyung Kim <namhyung@kernel.org>]

On Sun, Jul 26, 2026 at 08:52:36PM -0300, Arnaldo Carvalho de Melo wrote:
> On Sun, Jul 26, 2026 at 08:22:08PM -0300, Arnaldo Carvalho de Melo wrote:
> > Hi,
> > 
> > 	Getting back on track with perf I noticed these two flaky tests,
> > not investigated yet:
> 
> Sry, sent to another Ian, from another life :-)

:)

>  
> > ⬢ [acme@toolbx perf-tools-next]$ git log --oneline -1
> > 98bc7deff4858aa8 (HEAD -> perf/hardening-machine, number/perf/hardening-machine) perf machine: Check snprintf truncation for guest kallsyms path
> > ⬢ [acme@toolbx perf-tools-next]$ perf -v
> > perf version 7.2.rc1.g98bc7deff485
> > ⬢ [acme@toolbx perf-tools-next]$
> > logout
> > acme@x1:~/git/perf-tools-next$
> > acme@x1:~/git/perf-tools-next$ sudo su -
> > [sudo] password for acme:
> > root@x1:~# perf -vv
> > perf version 7.2.rc1.g98bc7deff485
> >                    aio: [ on  ]  # HAVE_AIO_SUPPORT
> >                    bpf: [ on  ]  # HAVE_LIBBPF_SUPPORT
> >          bpf_skeletons: [ on  ]  # HAVE_BPF_SKEL
> >             debuginfod: [ on  ]  # HAVE_DEBUGINFOD_SUPPORT
> >                  dwarf: [ on  ]  # HAVE_LIBDW_SUPPORT
> >     dwarf_getlocations: [ on  ]  # HAVE_LIBDW_SUPPORT
> >           dwarf-unwind: [ on  ]  # HAVE_DWARF_UNWIND_SUPPORT
> >                 libbfd: [ OFF ]  # HAVE_LIBBFD_SUPPORT ( tip: Deprecated, license incompatibility, use BUILD_NONDISTRO=1 and install binutils-dev[el] )
> > babeltrace2-ctf-writer: [ on  ]  # HAVE_BABELTRACE2_CTF_WRITER_SUPPORT
> >         libbpf-strings: [ on  ]  # HAVE_LIBBPF_STRINGS_SUPPORT
> >            libcapstone: [ on  ]  # HAVE_LIBCAPSTONE_SUPPORT
> >     libdw-dwarf-unwind: [ on  ]  # HAVE_LIBDW_SUPPORT
> >                 libelf: [ on  ]  # HAVE_LIBELF_SUPPORT
> >                libLLVM: [ on  ]  # HAVE_LIBLLVM_SUPPORT
> >                libnuma: [ on  ]  # HAVE_LIBNUMA_SUPPORT
> >             libopencsd: [ on  ]  # HAVE_CSTRACE_SUPPORT
> >                libperl: [ OFF ]  # HAVE_LIBPERL_SUPPORT ( tip: Deprecated, use LIBPERL=1 and install perl-ExtUtils-Embed/libperl-dev to build with it )
> >                libpfm4: [ on  ]  # HAVE_LIBPFM
> >              libpython: [ on  ]  # HAVE_LIBPYTHON_SUPPORT
> >               libslang: [ on  ]  # HAVE_SLANG_SUPPORT
> >          libtraceevent: [ on  ]  # HAVE_LIBTRACEEVENT
> >              libunwind: [ OFF ]  # HAVE_LIBUNWIND_SUPPORT ( tip: Deprecated, use LIBUNWIND=1 and install libunwind-dev[el] to build with it )
> >                   lzma: [ on  ]  # HAVE_LZMA_SUPPORT
> > numa_num_possible_cpus: [ on  ]  # HAVE_LIBNUMA_SUPPORT
> >                   zlib: [ on  ]  # HAVE_ZLIB_SUPPORT
> >                   zstd: [ on  ]  # HAVE_ZSTD_SUPPORT
> >                   rust: [ on  ]  # HAVE_RUST_SUPPORT
> > root@x1:~# perf test
[SNIP]
> > === Test Summary ===
> > Passed main tests : 133
> > Passed subtests   : 152
> > Skipped tests     : 24
> > Failed tests      : 2
> > List of failed tests:
> >    23: Object code reading
> >   110: perf record sample filtering (by BPF) tests
> > root@x1:~# perf test 23
> >  23: Object code reading                                                                                       : Ok

Right, I'm seeing this is flaky.  Sometimes it fails to find a map for
some kernel address.

> > 
> > === Test Summary ===
> > Passed main tests : 1
> > Passed subtests   : 0
> > Skipped tests     : 0
> > Failed tests      : 0
> > root@x1:~# perf test 110
> > 110: perf record sample filtering (by BPF) tests                                                               : Ok

I never saw this before.  Do you have error message?

Thanks,
Namhyung

> > 
> > === Test Summary ===
> > Passed main tests : 1
> > Passed subtests   : 0
> > Skipped tests     : 0
> > Failed tests      : 0
> > root@x1:~#