Comment 1 for bug 2049529

This also affects src:adduser, which has this delta:

+ if ($action eq "adduser") {
+ # Mute the command
+ system('sh' => ( '-c' => '"$@" >/dev/null 2>&1', '--', '/usr/sbin/zsysctl', 'userdata', 'create', $new_name, $home_dir,));
+ }

causing it to fail in minimal environments where /dev is non populated.

In practice we are hitting this with autopkgtest-virt-unshare(1), which tries to create a user in the chroot, but fails because of that.