website unavailable: potentially caused by memory leak of fwupd

I have a VPS that runs Ubuntu 24.04.1 LTS (GNU/Linux 6.8.0-85-generic x86_64). The system was out-of-memory, causing the website to be unavailable. The post documents my troubleshooting and diagnosis.

When I logged into the server with the website not responding, the stats were

 System information as of Fri Jan 16 10:12:48 UTC 2026

  System load:           0.18
  Usage of /:            87.9% of 23.17GB
  Memory usage:          84%
  Swap usage:            0%
  Processes:             117
  Users logged in:       0

I used top to see what processes were causing the load. "Shift+M" sorts by memory used.

top - 10:16:10 up 103 days, 12:20,  1 user,  load average: 0.03, 0.07, 0.03
Tasks: 113 total,   1 running, 112 sleeping,   0 stopped,   0 zombie
%Cpu(s):  2.6 us,  1.9 sy,  0.0 ni, 95.1 id,  0.4 wa,  0.0 hi,  0.0 si,  0.0 st 
MiB Mem :    961.6 total,     68.4 free,    905.6 used,    127.0 buff/cache     
MiB Swap:      0.0 total,      0.0 free,      0.0 used.     56.0 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                  
1546860 username  20   0  962272 179692   1012 S   1.9  18.2 184:29.69 gunicorn                                                 
1546859 username  20   0  953968 171696   1020 S   1.9  17.4 159:19.89 gunicorn                                                 
1578333 root      20   0  689004 144056   4176 S   0.0  14.6   0:10.57 fwupd                                                    
    885 root      20   0 2001968  44176  12744 S   0.0   4.5  55:52.04 dockerd                                                  
    325 root      rt   0  288952  27136   8704 S   0.0   2.8  13:08.03 multipathd                                               
    796 root      20   0 1727032  23024   9088 S   0.0   2.3 120:22.17 containerd                                               
1493204 root      20   0 1850364  19216   4352 S   0.0   2.0  66:57.05 snapd                                                    
1546725 username  20   0   64908  15352    768 S   0.0   1.6   1:07.85 gunicorn                                                 
1565013 do-agent  20   0 1238600  14364   8704 S   0.0   1.5   1:08.77 do-agent                                                 
    277 root      19  -1  124224  13840  12620 S   0.0   1.4  16:00.35 systemd-journal                                          
    847 root      20   0  110012  12800   3456 S   0.0   1.3   0:00.12 unattended-upgr  

The thread (https://github.com/fwupd/fwupd/issues/6948) indicates fwupd (a system daemon to allow session software to update firmware) has had memory leaks.

The post (https://www.reddit.com/r/debian/comments/1gilrlm/howto_device_firmware_updates_with_fwupd/) has commands but I didn't use that.

I used sudo reboot and then, once the system was up, the usage was

 System information as of Fri Jan 16 10:25:22 UTC 2026

  System load:           0.06
  Usage of /:            87.7% of 23.17GB
  Memory usage:          51%
  Swap usage:            0%
  Processes:             108
  Users logged in:       0

I then ran

sudo apt update
sudo apt upgrade