ip6 regressions end of November 2025

[vrpolakatcisco]

While results with AVF driver are also affected by #4109, looking at trending [0] this might be two different regressions, 2n-zn2 being affected few days sooner than others. 2n-grc is not affected by this (only by #4110), so this might be something Intel-specific.

Deeper investigation is needed.

[0] non-avf 2-node ip6base

[vrpolakatcisco]

For 2n-zn2, the cause was confirmed [1] to be:
43698: vppinfra: fix bihash atomicity and garbage values | https://gerrit.fd.io/r/c/vpp/+/43698

[1] https://gerrit.fd.io/r/c/vpp/+/43698/6#message-e6d06e193ea0665f87c9f9f8b9fc6d9c8f07f7b1

[vrpolakatcisco]

And for xeons it was [2] the subsequent bihash change:
44018: vppinfra: add secondary key verification to bihash | https://gerrit.fd.io/r/c/vpp/+/44018

[2] https://gerrit.fd.io/r/c/vpp/+/44018/2#message-3610dfb9d9e6c51624f4ccc7df9c3354d589c714