When booting the RPi3, everything seems normal and the login console appears.
However, entering any login name (e.g. root) and hitting enter leads to the login console going away and reappearing -
as if the login name was rejected, the login failure lockout got triggered, or the login process is crashing (which is what's
actually happening).
We shut down the RPi by hitting Ctrl-Alt-Del and removing the power once it is done with the shutdown process
(you may be able to perform SysRq-REISUO to perform an emergency
sync,unmount,halt instead if you have the Magic SysRq key enabled)
We remove the SD-Card from the RPi and insert it into an SD Card Reader connected to our Arch laptop, and mount the rootfs:
sudo blkid # identify SDCard partitions
export DEV=sdd # replace sdd by SDCard device determined from blkid command's output
sudo mkdir -p /mnt/${DEV}
sudo mount /dev/${DEV}2 /mnt/${DEV}
sudo mount /dev/${DEV}1 /mnt/${DEV}/boot # mount /boot partition
Now we get a root shell chdir'd into the RPi rootfs:
$ sudo -i
# cd /mnt/sdd
And now we can do cool stuff like reading the journal:
journalctl -D var/log/journal/ -b
Or running pacman:
sudo pacman -r . --config etc/pacman.conf -Qkk
Please note the relative paths specified in the above two commands!
In the journal (see journal command mentioned before) we find this:
May 13 12:13:28 alarmpi systemd-coredump[328]: Process 321 (login) of user 0 dumped core.
Stack trace of thread 321:
#0 0x0000000076f1cf8c _dl_check_map_versions (ld-linux-armhf.so.3)
This means something is very wrong.