Re: [PATCH bpf-next v2 6/6] selftests/bpf: fix file descriptor assertion in open_tuntap helper

From: Marcus Wichelmann
Date: Wed Feb 19 2025 - 09:59:50 EST


Am 18.02.25 um 02:56 schrieb Willem de Bruijn:
Marcus Wichelmann wrote:
[...]
When running the BPF selftests locally, this incorrect assertion was not
an issue, but the BPF kernel-patches CI failed because of this:

open_tuntap:FAIL:open(/dev/net/tun) unexpected open(/dev/net/tun):
actual 0 <= expected 0

Wow. What kind of environment is this that 0 is not assigned stdin.
Signed-off-by: Marcus Wichelmann <marcus.wichelmann@xxxxxxxxxxxxxxxx>

The code makes sense.

I suppose that if this condition can hit, then it can also affect
existing lwt_* tests and thus should be a fix to commit 43a7c3ef8a15
("selftests/bpf: Add lwt_xmit tests for BPF_REDIRECT"), sent
separately to bpf (not bpf-next)?

Since it's a test and no failure was reported so far, maybe fine
to just merge as part of this bpf-next series, not my call.
I'm not sure why this only became an issue after I added the
xdp_context_tuntap test and never before. This may have to do with
the order of test execution.

If nobody speaks up, I'll leave it in this patch series for now.

Marcus