Re: [PATCH bpf-next v2] selftests/bpf: Track test_xdp_features DUT processes

[Bochao Cao]

 Thanks Daniel, Alexis, and Emil.

  Moving the test to tools/testing/selftests/drivers/net/hw/ appears to
  require more than relocating the shell script. The xdp_features userspace
  tool, BPF program, skeleton build rules, and test environment would also
  need to be adapted to the net driver selftest framework.

  Would it be acceptable to take the process lifecycle fix as a v3 in its
  current location, followed by a separate migration series?

  I would also be happy to work on the migration. If you would prefer to
  see the migration before this fix is applied, I can prepare v3 as a
  small series, keeping the framework migration and the process lifecycle
  changes separate where practical.

  Thanks,
  Bochao

Emil Tsalapatis <emil@xxxxxxxxxxxxxxx> 于2026年9月2日周三 15:44写道：


Emil Tsalapatis <emil@xxxxxxxxxxxxxxx> 于2026年9月2日周三 15:44写道：
>
> On Fri Aug 28, 2026 at 5:32 AM EDT, Bochao Cao wrote:
> >  Resending as plain text because my previous reply was rejected by the
> > vger mailing lists. Sorry for the duplicate.
> >  Thanks Daniel and Alexis.
> >
> >   Dropping the procps dependency is not the primary motivation for
> >   this change. I agree that Debian can remove the dependency independently.
> >   The issue addressed by this patch is process isolation in the standalone
> >   test. The current readiness check may observe an unrelated
> >   concurrent xdp_features process, while cleanup may terminate every
> > xdp_features
> >   process on the host. In addition, a DUT which exits before listening
> > can leave the test waiting indefinitely.
> >
> >   Although this script is not currently run by the BPF CI, it remains
> > useful  for testing real hardware,
> >   so these process lifecycle issues can still  affect users running
> > the test manually.
> >
> >   Would it be acceptable to fix these issues in the script's current location?
> >   If the preferred direction is to move it under
> > tools/testing/selftests/drivers/net/hw/,
> >   should the move be submitted first, with this fix rebased on top?
> >
> >   I can send a v3 that drops the Debian Closes tag and focuses
> >   the commit message solely on the process isolation, timeout,
> >   and cleanup fixes once the preferred location is clear.
> >
> >   Thanks,
> >   Bochao
>
> While I'd defer to Daniel and Alexis on this, imo we could merge the fix
> as-is and move the file as a followup since the change is a net gain on
> its own.
>
> Wherever we end up putting the file feel free to add:
>
> Reviewed-by: Emil Tsalapatis <emil@xxxxxxxxxxxxxxx>
>
> >
> >
> > Bochao Cao <bochaolucky@xxxxxxxxx> 于2026年8月28日周五 14:10写道：
> >>
> >>  Thanks Daniel and Alexis.
> >>
> >>   Dropping the procps dependency is not the primary motivation for
> >>   this change. I agree that Debian can remove the dependency independently.
> >>   The issue addressed by this patch is process isolation in the standalone
> >>   test. The current readiness check may observe an unrelated
> >>   concurrent xdp_features process, while cleanup may terminate every xdp_features
> >>   process on the host. In addition, a DUT which exits before listening can leave the test waiting indefinitely.
> >>
> >>   Although this script is not currently run by the BPF CI, it remains useful  for testing real hardware,
> >>   so these process lifecycle issues can still  affect users running the test manually.
> >>
> >>   Would it be acceptable to fix these issues in the script's current location?
> >>   If the preferred direction is to move it under tools/testing/selftests/drivers/net/hw/,
> >>   should the move be submitted first, with this fix rebased on top?
> >>
> >>   I can send a v3 that drops the Debian Closes tag and focuses
> >>   the commit message solely on the process isolation, timeout,
> >>   and cleanup fixes once the preferred location is clear.
> >>
> >>   Thanks,
> >>   Bochao
> >>
> >> Bochao Cao <bochaolucky@xxxxxxxxx> 于2026年8月25日周二 21:01写道：
> >> >
> >> >   Thanks Daniel and Alexis.
> >> >
> >> >   Dropping the procps dependency is not the primary motivation for
> >> >   this change. I agree that Debian can remove the dependency independently.
> >> >   The issue addressed by this patch is process isolation in the standalone
> >> >   test. The current readiness check may observe an unrelated
> >> >   concurrent xdp_features process, while cleanup may terminate every xdp_features
> >> >   process on the host. In addition, a DUT which exits before listening can leave the test waiting indefinitely.
> >> >
> >> >   Although this script is not currently run by the BPF CI, it remains useful  for testing real hardware,
> >> >   so these process lifecycle issues can still  affect users running the test manually.
> >> >
> >> >   Would it be acceptable to fix these issues in the script's current location?
> >> >   If the preferred direction is to move it under tools/testing/selftests/drivers/net/hw/,
> >> >   should the move be submitted first, with this fix rebased on top?
> >> >
> >> >   I can send a v3 that drops the Debian Closes tag and focuses
> >> >   the commit message solely on the process isolation, timeout,
> >> >   and cleanup fixes once the preferred location is clear.
> >> >
> >> >   Thanks,
> >> >   Bochao
> >> >
> >> > Alexis Lothoré <alexis.lothore@xxxxxxxxxxx> 于2026年8月24日周一 22:49写道：
> >> >>
> >> >> Hi Daniel, thanks for the notification
> >> >>
> >> >> On Mon Aug 24, 2026 at 1:31 PM CEST, Daniel Borkmann wrote:
> >> >> > [ Trimming the excessive Cc list, and adding Alexis ]
> >> >> >
> >> >> > On 8/12/26 10:28 AM, Bochao Cao via B4 Relay wrote:
> >> >> >> From: Bochao Cao <bochaolucky@xxxxxxxxx>
> >> >> >>
> >> >> >> test_xdp_features.sh waits for any xdp_features listener to appear and
> >> >> >> uses pidof during cleanup. A concurrent test can therefore make another
> >> >> >> test proceed before its own DUT is ready, and cleanup kills every
> >> >> >> xdp_features process on the host. The readiness loop also has no timeout,
> >> >> >> so a DUT that exits before listening leaves the test hung indefinitely.
> >> >> >>
> >> >> >> Track one active DUT at a time, wait for ss to report that exact PID with
> >> >> >> a bounded retry loop, and reap it after each test. Consult the shell job
> >> >> >> table before signaling the DUT so a stale PID cannot target an unrelated
> >> >> >> process. On failure, terminate the shell job with SIGKILL and reap it so
> >> >> >> blocked I/O cannot hang cleanup. Install an EXIT trap and signal handlers
> >> >> >> so failure paths also remove network setup.
> >> >> >>
> >> >> >> Fixes: 4dba3e7852b7 ("selftests/bpf: introduce XDP compliance test tool")
> >> >> >> Closes: https://bugs.debian.org/1136522
> >> >> >> Signed-off-by: Bochao Cao <bochaolucky@xxxxxxxxx>
> >> >> >> ---
> >> >> >> Tests:
> >> >> >> - bash -n tools/testing/selftests/bpf/test_xdp_features.sh
> >> >> >> - make -C tools/testing/selftests/bpf xdp_features
> >> >> >> - sudo tools/testing/selftests/bpf/test_xdp_features.sh
> >> >> >> - verified cleanup terminates a blocked DUT without affecting an unrelated process
> >> >> >> ---
> >> >> >> Changes in v2:
> >> >> >> - Clarify that avoiding name-wide process matching, rather than dropping a dependency, is the motivation.
> >> >> >> - Track and reap one active DUT at a time instead of retaining historical PIDs.
> >> >> >> - Address PID reuse by signaling only the current Bash job during cleanup.
> >> >> >> - Use SIGKILL on failure cleanup so blocked DUT I/O cannot hang wait indefinitely.
> >> >> >> - Link to v1: https://patch.msgid.link/20260805-xdp-dut-process-lifecycle-gmail-v1-1-45984df8d295@xxxxxxxxx
> >> >> >> ---
> >> >> >>   tools/testing/selftests/bpf/test_xdp_features.sh | 82 ++++++++++++++++++------
> >> >> >>   1 file changed, 62 insertions(+), 20 deletions(-)
> >> >> >
> >> >> > Sorry for the late reply. With regards to https://bugs.debian.org/1136522, src:linux deb
> >> >> > does not have to depend on this at all, so the src:linux can just get rid of procps in
> >> >> > any case if this is indeed the last dependency. I'm not seeing the test being run in our
> >> >> > BPF CI. I've Cc'ed Alexis as he's in the process of migrating and/or removing tests from
> >> >> > tools/testing/selftests/bpf/ depending on how they fit into test_progs framework. I'll
> >> >> > let him comment if there is already work in progress. It feels like this script could be
> >> >> > reworked into tools/testing/selftests/drivers/net/hw/ tests and removed altogether from
> >> >> > the tools/testing/selftests/bpf/ dir.
> >> >>
> >> >> There has been an attempt to fully convert and get rid of
> >> >> test_xdp_features.sh, but discussions around the corresponding series
> >> >> highlighted the need for the script to remain available for testing on
> >> >> real hardware.  Features covered by the test_xdp_features.sh that were
> >> >> not covered yet by test_progs have been added to test_progs (in
> >> >> xdp_cpumap_attach), see [1]. So there's currently no active effort on
> >> >> this one on my side.
> >> >>
> >> >> Alexis
> >> >>
> >> >> [1] https://lore.kernel.org/bpf/20241009-convert_xdp_tests-v3-0-51cea913710c@xxxxxxxxxxx/
> >> >>
> >> >> --
> >> >> Alexis Lothoré, Bootlin
> >> >> Embedded Linux and Kernel engineering
> >> >> https://bootlin.com
> >> >>
>