[Bug]: xqc_hq_parse_req|247||hq recv CR LF|

[larseggert]

What happened?

The quic-interop-runner zerortt test case with neqo as a client and xquic at the server times out after several minutes. I tried to debug this, but on the xquic side, all I see in the logs is the line

xqc_hq_parse_req|247||hq recv CR LF|

which repeats thousands of times. On the neqo side, this is the last packet received from xquic, with nothing afterwards:

0.871 DEBUG [Client 904506e79861148e] pn=1 type=Handshake pri-path:c5cee15db60a03f6f41bd99a 0.0.0.0:44601->193.167.100.100:443 Tos(Cs0, NotEct) len 81
  -> RX Crypto { offset: 142, len: 36 }

i.e., this is the final server handshake packets that installs the application-space keys. (Full log: log.txt.gz)

Steps To Reproduce

uv run python3.13 ./run.py -c neqo -s xquic -t zerortt -d

with an installation of the interop runner.

Relevant log output

See above.

[Sy0307]

Sorry for dismissing this issue, I will find the root cause and try to fix it. Thanks!
The similar issue is #518.