When pam_namespace is implementing polyinstantiated mounts, mounts/unmounts performed in one 'su' session are not propagated to other login sessions

Issue

If polyinstantiated mounts are in use, a mount/unmount performed in a su root shell or via sudo will not be available in other login sessions.

Example:

session 1:
[user@server ~]$ su -
Password:
[root@server ~]# mount nfsserver:/exports /mnt/nfsserver
[root@server ~]# grep nfsserver /proc/self/mountinfo
436 435 0:43 / /mnt/nfsserver rw,relatime - nfs4 nfsserver:/exports rw,seclabel,vers=4.2,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,clientaddr=192.168.122.50,local_lock=none,addr=192.168.122.73

session 2:
[user@server ~]$ grep nfsserver /proc/self/mountinfo