What were you trying to do that didn't work?

1. top -u <username>

press "M" to sort by memory usage

Please provide the package NVR for which bug is seen:

procps-ng-3.3.17-11.el9.x86_64

How reproducible:

Consistently even on a fresh install.

Steps to reproduce

There are multiple ways to reproduce this issue: 

A: 

1. I have a user "test" who currently has two ssh sessions which are each watching a log file. As the root user, I execute "top -u test":
   -------------------------------
2. top -u test

top - 11:34:11 up 15 days,  3:17,  4 users,  load average: 0.00, 0.00, 0.00
Tasks: 111 total,   1 running, 110 sleeping,   0 stopped,   0 zombie
%Cpu(s):  0.0 us,  0.3 sy,  0.0 ni, 99.7 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
MiB Mem :   1766.2 total,   1111.2 free,    356.0 used,    446.8 buff/cache
MiB Swap:      0.0 total,      0.0 free,      0.0 used.   1410.2 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND 
  22696 test      20   0    8816   5564   3520 S   0.0   0.3   0:00.02 bash    
  22723 test      20   0    8684   5500   3540 S   0.0   0.3   0:00.01 bash    
  22744 test      20   0    6156   2820   2420 S   0.0   0.2   0:00.14 watch   
  22764 test      20   0    6156   2804   2408 S   0.0   0.2   0:00.13 watch   
-------------------------------

1. Pressing "M" results in no processes showing: 
   -------------------------------
   top - 11:35:00 up 15 days,  3:18,  4 users,  load average: 0.00, 0.00, 0.00
   Tasks: 111 total,   1 running, 110 sleeping,   0 stopped,   0 zombie
   %Cpu(s):  0.3 us,  0.7 sy,  0.0 ni, 98.3 id,  0.0 wa,  0.3 hi,  0.0 si,  0.3 st
   MiB Mem :   1766.2 total,   1111.2 free,    356.0 used,    446.8 buff/cache
   MiB Swap:      0.0 total,      0.0 free,      0.0 used.   1410.2 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND 
-------------------------------

B: 

1. This can also be reproduced by executing "top", then searching for a specific user and sorting with M. While the same test user is logged in with the same processes running in another console, I execute simply "top" as the root user, then press "u" and enter "test" to show only processes owned by the test user: 
   -------------------------------
   top - 11:37:06 up 15 days,  3:20,  4 users,  load average: 0.00, 0.00, 0.00
   Tasks: 111 total,   1 running, 110 sleeping,   0 stopped,   0 zombie
   %Cpu(s):  0.3 us,  0.7 sy,  0.0 ni, 98.7 id,  0.0 wa,  0.3 hi,  0.0 si,  0.0 st
   MiB Mem :   1766.2 total,   1111.2 free,    356.0 used,    446.8 buff/cache
   MiB Swap:      0.0 total,      0.0 free,      0.0 used.   1410.2 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND 
  22764 test      20   0    6156   2804   2408 S   0.3   0.2   0:00.22 watch   
  22681 test      20   0   22360  14392  11244 S   0.0   0.8   0:00.15 systemd 
  22683 test      20   0  173456   7236      0 S   0.0   0.4   0:00.00 (sd-pa+ 
  22695 test      20   0   20612   7872   5712 S   0.0   0.4   0:00.15 sshd    
  22696 test      20   0    8816   5564   3520 S   0.0   0.3   0:00.02 bash    
  22722 test      20   0   20616   7912   5748 S   0.0   0.4   0:00.15 sshd    
  22723 test      20   0    8684   5500   3540 S   0.0   0.3   0:00.01 bash    
  22744 test      20   0    6156   2820   2420 S   0.0   0.2   0:00.21 watch 
-------------------------------

1. If I then press "M" to sort by memory, the processes disappear again: 
   -------------------------------
   top - 11:37:47 up 15 days,  3:21,  4 users,  load average: 0.00, 0.00, 0.00
   Tasks: 111 total,   1 running, 110 sleeping,   0 stopped,   0 zombie
   %Cpu(s):  0.0 us,  2.0 sy,  0.0 ni, 96.0 id,  0.0 wa,  2.0 hi,  0.0 si,  0.0 st
   MiB Mem :   1766.2 total,   1111.2 free,    356.0 used,    446.8 buff/cache
   MiB Swap:      0.0 total,      0.0 free,      0.0 used.   1410.2 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND 
-------------------------------

Expected results

Sorting a particular user's processes by memory should not cause top to fail. 

Actual results

Top stops showing processes if you limit the results to a specific user and then sort by memory. 

Additional notes:

If I run "top" as the test user, and then press "M", the processes are sorted by memory usage as expected and do not disappear. 

Additionally, if "top" is executed by the root user and you sort with "M" first and then limit the processes to a single user with "u", the processes are still displayed and sorted by memory usage as expected.