glibc/2.33-0ubuntu5 ADT test failure with linux-kvm/5.11.0-1021.23

This is a scripted bug report about ADT failures while running glibc tests for linux-kvm/5.11.0-1021.23 on hirsute. Whether this is caused by the dep8 tests of the tested source or the kernel has yet to be determined.

Testing failed on:
    amd64: https://autopkgtest.ubuntu.com/results/autopkgtest-hirsute/hirsute/amd64/g/glibc/20211203_232031_b8a9a@/log.gz

glibc encounters a timeout during testing:
autopkgtest [22:42:14]: ERROR: timed out on command "su -s /bin/bash ubuntu -c set -e; export USER=`id -nu`; . /etc/profile >/dev/null 2>&1 || true; . ~/.profile >/dev/null 2>&1 || true; buildtree="/tmp/autopkgtest.Rcv9bW/build.fYR/src"; mkdir -p -m 1777 -- "/tmp/autopkgtest.Rcv9bW/rebuild-artifacts"; export AUTOPKGTEST_ARTIFACTS="/tmp/autopkgtest.Rcv9bW/rebuild-artifacts"; export ADT_ARTIFACTS="$AUTOPKGTEST_ARTIFACTS"; mkdir -p -m 755 "/tmp/autopkgtest.Rcv9bW/autopkgtest_tmp"; export AUTOPKGTEST_TMP="/tmp/autopkgtest.Rcv9bW/autopkgtest_tmp"; export ADTTMP="$AUTOPKGTEST_TMP"; export DEBIAN_FRONTEND=noninteractive; export LANG=C.UTF-8; export DEB_BUILD_OPTIONS=parallel=4; unset LANGUAGE LC_CTYPE LC_NUMERIC LC_TIME LC_COLLATE LC_MONETARY LC_MESSAGES LC_PAPER LC_NAME LC_ADDRESS LC_TELEPHONE LC_MEASUREMENT LC_IDENTIFICATION LC_ALL;rm -f /tmp/autopkgtest_script_pid; set -C; echo $$ > /tmp/autopkgtest_script_pid; set +C; trap "rm -f /tmp/autopkgtest_script_pid" EXIT INT QUIT PIPE; cd "$buildtree"; export 'ADT_TEST_TRIGGERS=linux-meta-kvm/5.11.0.1021.22 linux-kvm/5.11.0-1021.23 linux-signed-kvm/5.11.0-1021.23'; chmod +x /tmp/autopkgtest.Rcv9bW/build.fYR/src/debian/tests/rebuild; touch /tmp/autopkgtest.Rcv9bW/rebuild-stdout /tmp/autopkgtest.Rcv9bW/rebuild-stderr; /tmp/autopkgtest.Rcv9bW/build.fYR/src/debian/tests/rebuild 2> >(tee -a /tmp/autopkgtest.Rcv9bW/rebuild-stderr >&2) > >(tee -a /tmp/autopkgtest.Rcv9bW/rebuild-stdout);" (kind: test)
autopkgtest [22:42:14]: test rebuild: -----------------------]
autopkgtest [22:42:20]: test rebuild: - - - - - - - - - - results - - - - - - - - - -
rebuild FAIL timed out
autopkgtest [22:42:20]: @@@@@@@@@@@@@@@@@@@@ summary
rebuild FAIL timed out