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

[Daniel Borkmann <daniel@iogearbox.net>]

[ 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@gmail.com>
> 
> 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@gmail.com>
> ---
> 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@gmail.com
> ---
>   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.