My friend was running firefox on linux mint, and it froze and he used xkill to kill firefox. But still it shows up in htop ps -aux. He tried to kill it multiple times but it didn’t work. See the pictures for explanation. We had to kill power to shutdown, even systemd can’t stop that process.
First of all: make sure to kill the right process. The process selected in your
htopscreenshot is just a random render process, that won’t take out the browser itself. You need to kill the parent process for that.If
kill -9doesn’t work, it may be a zombie process or it may be stuck in a syscall waiting on some kind of I/O operation that isn’t timing out/is bugged out/can never complete. For example, if it has done a call into the GPU driver while the GPU driver bugged out, it may be stuck waiting forever.Normally, zombie processes should terminate when their parent gets killed. However, if the process is orphaned (the parent process died/was killed), init (whatever PID 1 may be on your system) will adopt the process, becoming its new parent, and take over the responsibility to read the exit code.
systemd’s init should reap zombie orphans so I believe this is likely I/O or driver related.
If a system is stuck shutting down, you can often force it by pressing ctrl+alt+delete seven times in a row. If that doesn’t work, the magic SysRq key combos may help force reboot/halt the system; however, those are often disabled by default so they may be useless when you actually encounter a situation like this.
Yes, I killed the parent process. Also after killing the process with firefox PID, the file equivalent to that process
/proc/PIDwas still there. I think it could be - “likely I/O or driver related” or “stuck in a syscall waiting on some kind of I/O operation that isn’t timing out/is bugged out/can never complete”.