Order of mounting of entries in a mount namespace

I'm aware of unshare -m creates a new mount namespace moving the process executing it into the new mount namespace being created. The latter gets a *copy* of parent's mount namespace. Indeed look at the following root@ubuntu:~# cat /proc/self/mountinfo 25 31 0:23 / /sys rw,nosuid,nodev,noexec,relatime shared:7 - sysfs sysfs rw 26 31 0:24 / /proc rw,nosuid,nodev,noexec,relatime shared:12 - proc proc rw 27 31 0:5 / /dev rw,nosuid,relatime shared:2 - devtmpfs udev rw,size=4008708k,nr_inodes=1002177,mode=755,inode64 28 27 0:25 / /dev/pts rw,nosuid,noexec,relatime shared:3 - devpts devpts rw,gid=5,mode=620,ptmxmode=000 29 31 0:26 / /run rw,nosuid,nodev,noexec,relatime shared:5 - tmpfs tmpfs rw,size=812844k,mode=755,inode64 31 1 8:2 / / rw,relatime shared:1 - ext4 /dev/sda2 rw 32 25 0:6 / /sys/kernel/security rw,nosuid,nodev,noexec,relatime shared:8 - securityfs securityfs rw 33 27 0:28 / /dev/shm rw,nosuid,nodev shared:4 - tmpfs tmpfs rw,inode64 34 29 0:29 / /run/lock rw,nosuid,nodev,noexec,relatime shared:6 - tmpfs tmpfs rw,size=5120k,inode64 35 25 0:30 / /sys/fs/cgroup rw,nosuid,nodev,noexec,relatime shared:9 - cgroup2 cgroup2 rw,nsdelegate,memory_recursiveprot 36 25 0:31 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime shared:10 - pstore pstore rw 37 25 0:32 / /sys/fs/bpf rw,nosuid,nodev,noexec,relatime shared:11 - bpf bpf rw,mode=700 38 26 0:33 / /proc/sys/fs/binfmt_misc rw,relatime shared:13 - autofs systemd-1 rw,fd=29,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=17383 39 27 0:20 / /dev/mqueue rw,nosuid,nodev,noexec,relatime shared:14 - mqueue mqueue rw 40 27 0:34 / /dev/hugepages rw,relatime shared:15 - hugetlbfs hugetlbfs rw,pagesize=2M 41 25 0:7 / /sys/kernel/debug rw,nosuid,nodev,noexec,relatime shared:16 - debugfs debugfs rw 42 25 0:12 / /sys/kernel/tracing rw,nosuid,nodev,noexec,relatime shared:17 - tracefs tracefs rw ---------------------------- output omitted ------------------------------------------ root@ubuntu:~# root@ubuntu:~# unshare -m /bin/bash root@ubuntu:~# root@ubuntu:~# cat /proc/self/mountinfo 714 713 8:2 / / rw,relatime - ext4 /dev/sda2 rw 715 714 0:5 / /dev rw,nosuid,relatime - devtmpfs udev rw,size=4008708k,nr_inodes=1002177,mode=755,inode64 716 715 0:25 / /dev/pts rw,nosuid,noexec,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=000 719 715 0:28 / /dev/shm rw,nosuid,nodev - tmpfs tmpfs rw,inode64 720 715 0:20 / /dev/mqueue rw,nosuid,nodev,noexec,relatime - mqueue mqueue rw 725 715 0:34 / /dev/hugepages rw,relatime - hugetlbfs hugetlbfs rw,pagesize=2M 726 714 0:26 / /run rw,nosuid,nodev,noexec,relatime - tmpfs tmpfs rw,size=812844k,mode=755,inode64 739 726 0:29 / /run/lock rw,nosuid,nodev,noexec,relatime - tmpfs tmpfs rw,size=5120k,inode64 740 726 0:36 / /run/credentials/systemd-sysusers.service ro,nosuid,nodev,noexec,relatime - ramfs none rw,mode=700 741 726 0:26 /snapd/ns /run/snapd/ns rw,nosuid,nodev,noexec,relatime - tmpfs tmpfs rw,size=812844k,mode=755,inode64 742 726 0:26 /netns /run/netns rw,nosuid,nodev,noexec,relatime - tmpfs tmpfs rw,size=812844k,mode=755,inode64 743 726 0:46 / /run/user/1000 rw,nosuid,nodev,relatime - tmpfs tmpfs rw,size=812840k,nr_inodes=203210,mode=700,uid=1000,gid=1000,inode64 744 714 0:23 / /sys rw,nosuid,nodev,noexec,relatime - sysfs sysfs rw 745 744 0:6 / /sys/kernel/security rw,nosuid,nodev,noexec,relatime - securityfs securityfs rw 746 744 0:30 / /sys/fs/cgroup rw,nosuid,nodev,noexec,relatime - cgroup2 cgroup2 rw,nsdelegate,memory_recursiveprot 747 744 0:31 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime - pstore pstore rw 748 744 0:32 / /sys/fs/bpf rw,nosuid,nodev,noexec,relatime - bpf bpf rw,mode=700 814 744 0:7 / /sys/kernel/debug rw,nosuid,nodev,noexec,relatime - debugfs debugfs rw 815 744 0:12 / /sys/kernel/tracing rw,nosuid,nodev,noexec,relatime - tracefs tracefs rw ---------------------------- output omitted ------------------------------------------ root@ubuntu:~# The outputs are slightly different, even though the mountpoint's parent-child dependencies are the same (different Ids in the first two columns are expected since mount namespaces are not the same). Now the question is: is there a reason behind the different order in which the mountpoints are actually shown ?