I'm running Ubuntu 21.04 on a Raspberry Pi 4B. I'm viewing top to monitor what's going on and it is showing at the moment 11 'tmux: server' processes. Tmux is running, showing one window containing four panes. tmux ls is showing only one tmux session and I am the only user on this system.
Top is looking like this:
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
442735 forkbeard 20 0 2112 92 0 R 26.3 0.0 158:41.99 sh
528026 forkbeard 20 0 9744 3284 0 R 26.3 0.0 20:52.28 tmux: server
437265 forkbeard 20 0 9744 3284 0 R 24.7 0.0 173:13.35 tmux: server
416513 forkbeard 20 0 2112 92 0 R 24.0 0.0 265:19.36 sh
518289 forkbeard 20 0 2112 92 0 R 24.0 0.0 36:45.63 sh
463927 forkbeard 20 0 9744 3284 0 R 23.7 0.0 118:41.86 tmux: server
429208 forkbeard 20 0 9744 3284 0 R 23.4 0.0 206:13.66 tmux: server
442671 forkbeard 20 0 9744 3284 0 R 23.4 0.0 158:40.05 tmux: server
518605 forkbeard 20 0 9744 3284 0 R 23.4 0.0 36:02.78 tmux: server
442526 forkbeard 20 0 9744 3284 0 R 23.1 0.0 159:29.68 tmux: server
454131 forkbeard 20 0 2112 92 0 R 23.1 0.0 135:06.35 sh
486599 forkbeard 20 0 9744 3284 0 R 23.1 0.0 81:16.72 tmux: server
498747 forkbeard 20 0 9744 3284 0 R 23.1 0.0 62:09.51 tmux: server
486415 forkbeard 20 0 9744 3284 0 R 22.8 0.0 81:28.65 tmux: server
534318 root 20 0 398672 11260 1964 R 22.8 0.1 10:38.05 rsync
528130 forkbeard 20 0 9744 3284 0 R 22.4 0.0 20:45.50 tmux: server
I have noticed this before on this machine and a reboot fixes it - but that's not a great solution. Killing the processes doesn't work, even as root; it doesn't give me an error but the process just keeps running.
If I'm listing the processes using ps I can also see the processes (first output line added for readability). What I find curious is the processes' start times: I am pretty sure I did not start any tmux sessions during the night.
root@rpi:/home/forkbeard# ps aux | grep [t]mux
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
forkbeard 295509 0.6 0.0 9876 5984 ? Ss Aug12 7:45 tmux
forkbeard 429208 33.2 0.0 9744 3284 ? R Aug12 209:02 tmux
forkbeard 437265 30.6 0.0 9744 3284 ? R Aug12 176:00 tmux
forkbeard 442526 29.5 0.0 9744 3284 ? R Aug12 162:18 tmux
forkbeard 442671 29.4 0.0 9744 3284 ? R Aug12 161:28 tmux
forkbeard 463927 27.5 0.0 9744 3284 ? R Aug12 121:29 tmux
forkbeard 486415 25.1 0.0 9744 3284 ? R 01:38 84:14 tmux
forkbeard 486599 25.1 0.0 9744 3284 ? R 01:38 84:05 tmux
forkbeard 498747 24.1 0.0 9744 3284 ? R 02:43 64:57 tmux
forkbeard 518605 22.4 0.0 9744 3284 ? R 04:19 38:50 tmux
forkbeard 528026 21.4 0.0 9744 3284 ? R 05:22 23:39 tmux
forkbeard 528130 21.4 0.0 9744 3284 ? R 05:22 23:34 tmux
forkbeard 549554 0.0 0.0 7000 3072 pts/2 S+ 07:10 0:00 tmux att
What's going on?
/edit:
pstree gives me this:
├─tmux: server─┬─bash───sudo───su───bash───watch
│ ├─bash───top
│ ├─bash───sudo───su───bash───pstree
│ ├─bash───sudo───su───bash───rsnapshot───rsync───rsync───rsync
│ ├─bash───sudo───su───bash
│ └─11*[tmux: server]
