Re: [PATCH v2 0/7] Perf stat --null/offline CPU segv related fixes/tests

[Ingo Molnar <mingo@kernel.org>]

* Ian Rogers <irogers@google.com> wrote:

> Ingo reported [1] that `perf stat --null` was segfaulting. Fix the
> underlying issue and add a test to the "perf stat tests". Do some
> related fixing/cleanup in the perf util cpumap code.
>
> Thomas reported an issue fixed by the same patches [2] but caused by
> giving perf stat an offline CPU. Add test coverage for that and
> improve the "error" message that reports "success".
>
> Ingo further pointed at broken signal handling in repeat mode [3]. I
> observed we weren't giving the best exit code, 0 rather than the
> expected 128+<signal number>. Add a patch fixing this.
>
> [1] https://lore.kernel.org/linux-perf-users/aSwt7yzFjVJCEmVp@gmail.com/
> [2] https://lore.kernel.org/linux-perf-users/94313b82-888b-4f42-9fb0-4585f9e90080@linux.ibm.com/
> [3] https://lore.kernel.org/lkml/aS5wjmbAM9ka3M2g@gmail.com/
>
> Ian Rogers (7):
>   perf stat: Allow no events to open if this is a "--null" run
>   libperf cpumap: Fix perf_cpu_map__max for an empty/NULL map
>   perf cpumap: Add "any" CPU handling to cpu_map__snprint_mask
>   perf tests stat: Add "--null" coverage
>   perf stat: When no events, don't report an error if there is none
>   perf tests stat: Add test for error for an offline CPU
>   perf stat: Improve handling of termination by signal
>
>  tools/lib/perf/cpumap.c        | 10 +++++----
>  tools/perf/builtin-stat.c      | 29 ++++++++++++++++++-------
>  tools/perf/tests/shell/stat.sh | 39 ++++++++++++++++++++++++++++++++++
>  tools/perf/util/cpumap.c       |  9 ++++++--
>  4 files changed, 73 insertions(+), 14 deletions(-)

A belated:

  Tested-by: Ingo Molnar <mingo@kernel.org>

And thank you a lot for doing these QoL fixes!

	Ingo