t5551 hangs ?

Hej,
I found 2 threads about hanging t5551, one in 2016, and one question
from Junio somewhen in 2017.
I have it reproducable here:
- Debian 8, 64 bit
- SSD
- Half-modern processor ;-)

The last thing I can see is: ok 29 - test allowanysha1inwant with unreachable ----------- A simplified ps -ef shows: /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /usr/sbin/apache2 -d /home/blalbla/t/trash directory.t5551-http-fetch-smart/httpd -f /home/blalbla/t/lib-httpd/apache.conf -c Listen 127.0.0.1:5551 -k start /home/blalbla/git -C too-many-refs fetch -q --tags /home/blalbla/git-remote-http origin http://127.0.0.1:5551/smart/repo.git ------------- The tests passes on another box (real old laptop, spinning disk)

Anything that can be done to debug it ?