Package: sbuild Version: 0.85.8 Hi Johannes and Jochen,
while working with debusine.debian.net, I ran into a rather crazier kind of issue with the unshare backend. It seems like debusine.debian.net creates a chroot.tar where resolv.conf is a symbolic link: | lrwxrwxrwx 0/0 0 2024-05-20 17:15 ./etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf Notably, /run/systemd/resolve does not exist inside the tar nor does sbuild run systemd-resolved nor systemd-tmpfiles for creating this location. When building, the unshare backend tries to bind mount /etc/resolv.conf: | --: 13: cannot create /tmp/tmp.sbuild.OQ0pOU6LQg/etc/resolv.conf: Directory nonexistent https://debusine.debian.net/artifact/427489/hostname_3.23+nmu2_amd64-2024-05-24T10:06:30Z.build This fails, because mount attempts to dereference the symbolic link and finds that an intermediate directory does not exist. As a result, this fails and network generally does not work resulting in all sorts of badness. Technically speaking, you can bind mount onto a symbolic link. You just cannot do so using the mount(2) API nor the mount(1) command. Unless you pass MOVE_MOUNT_T_SYMLINKS to move_mount(2), it will not dereference a symlink being pointed at. I'm not sure we want to go this extra mile though. On the debusine side, I think we want to work around this issue in some way to avoid imposing a high version constraint in sbuild. I am reporting it here as it kinda is a bug (up to your judgement) and it helps having the diagnosis written down. Helmut
