Created attachment 876651 [details]
output - ps -ef

Issue:
  lsof 4.99 reports "Operation not permitted" on some processes (eg postfix)
  (only within LXC)  

Environment
  LXC container (unprivileged, nesting=1) based on PROXMOX
  OS within container openSUSE 15.6
  AppArmor + SElinux (per default) disabled
  Btw: bare-systems or VM's are not affected)

Side-Effekts
  zypper ps -s / zypper ps -sss reports always the postfix
   reboot complete container won't help

My workaround:
  reinstall old lsof (version 4.91 from openSUSE 15.5) and zypper worked well.

My commands & attachments:
   cd /tmp
   ps -ef > /tmp/ps-ef.lst
   zypper ps      > zypper-ps.lst
   zypper ps -s   > zypper-ps-s.lst
   zypper ps -sss > zypper-ps-sss.lst
   lsof-491.bin -p $(pgrep master) > lsof-491-master.lst 
   lsof-499.bin -p $(pgrep master) > lsof-499-master.lst

   strace -f -s 1024 -o strace-lsof-491.lst lsof-491.bin -p $(pgrep master)
   strace -f -s 1024 -o strace-lsof-499.lst lsof-499.bin -p $(pgrep master)