Re: [PATCH bpf-next v3 0/5] bpftool: Make probes which emit dmesg warnings optional

On 2/26/20 12:17 PM, Quentin Monnet wrote:

2020-02-25 20:44 UTC+0100 ~ Michal Rostecki [off-list ref]

quoted

Feature probes in bpftool related to bpf_probe_write_user and
bpf_trace_printk helpers emit dmesg warnings which might be confusing
for people running bpftool on production environments. This patch series
addresses that by filtering them out by default and introducing the new
positional argument "full" which enables all available probes.

The main motivation behind those changes is ability the fact that some
probes (for example those related to "trace" or "write_user" helpers)
emit dmesg messages which might be confusing for people who are running
on production environments. For details see the Cilium issue[0].

v1 -> v2:
- Do not expose regex filters to users, keep filtering logic internal,
expose only the "full" option for including probes which emit dmesg
warnings.

v2 -> v3:
- Do not use regex for filtering out probes, use function IDs directly.
- Fix bash completion - in v2 only "prefix" was proposed after "macros",
   "dev" and "kernel" were not.
- Rephrase the man page paragraph, highlight helper function names.
- Remove tests which parse the plain output of bpftool (except the
   header/macros test), focus on testing JSON output instead.
- Add test which compares the output with and without "full" option.

[0] https://github.com/cilium/cilium/issues/10048

Michal Rostecki (5):
   bpftool: Move out sections to separate functions
   bpftool: Make probes which emit dmesg warnings optional
   bpftool: Update documentation of "bpftool feature" command
   bpftool: Update bash completion for "bpftool feature" command
   selftests/bpf: Add test for "bpftool feature" command

  .../bpftool/Documentation/bpftool-feature.rst |  19 +-
  tools/bpf/bpftool/bash-completion/bpftool     |   3 +-
  tools/bpf/bpftool/feature.c                   | 283 +++++++++++-------
  tools/testing/selftests/.gitignore            |   5 +-
  tools/testing/selftests/bpf/Makefile          |   3 +-
  tools/testing/selftests/bpf/test_bpftool.py   | 179 +++++++++++
  tools/testing/selftests/bpf/test_bpftool.sh   |   5 +
  7 files changed, 374 insertions(+), 123 deletions(-)
  create mode 100644 tools/testing/selftests/bpf/test_bpftool.py
  create mode 100755 tools/testing/selftests/bpf/test_bpftool.sh

This version looks good to me, thanks!

Reviewed-by: Quentin Monnet <redacted>

(Please keep Acked-by/Reviewed-by tags between versions if there are no
significant changes, here for patch 1.)

Sorry, I will do that next time.

That's a lot of tests now that we don't have the regex and filtering is
very straightforward, but it does not hurt. I checked and they all pass
on my system.

I know that those tests were necessary with the regex implementation and
now they may seem to be an overkill. But on the other hand, I think that
having selftests for bpftool in general is a good thing, so I didn't
want throw them away despite the easier implementation of my patches. I
might follow up with some more tests covering the other subcommands in
future.

Cheers,
Michal