`pkill -9 -f firefox` won't work, what can be a possible explanation?

antihero@social.fossware.space to Linux@lemmy.ml – 21 points –

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.

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kill takes a process ID (i.e. a number) not a process name. Either find the right PID with ps first or use killall, although be aware that killall does exactly what it says: kills all processes matching the string it is given. If you only want to kill one of several Firefox processes that isn't what you want.

Sorry my mistake, it was pkill, but we also tried kill with process id, and we also tried killall. Every method that I knew i tried.

Stuck in kernel code, possibly because they tripped an assert. Even if not, if your distribution enabled hung task detection, the kernel will log backtraces for these processes eventually; by default, after 2 minutes of being stuck.

I knew it was something related to kernel. Now I have some some explanation of if this happens again.

You can cat /proc/PID/stack to see what it's wedged on in kernel land.

I'm guessing maybe something related to the GPU, maybe some kind of driver bug?

Did you literally type kill -9 firefox? Because the kill command normally takes PIDs not process names. killall takes process names, but process names are not always straightforward. Under normal circumstances firefox would exit when X/Wayland goes away though.

Using the sysrq key in the "reverse BUSIER" sequence when your system won't shutdown/reboot is always better than shutting the power on a running system.

Sorry, it was a mistake, I fixed the post. Also I tried many other ways to kill that process. Thanks for the BUSIER tip.