Direct Question: Flash under firefox 4.0, npviewer.bin, in KUbuntu 10.04 was running at 100% and I couldn't kill it. I tried:
sudo kill -9 12996
sudo kill -15 12996
I logged in as root and ran both commands. The PPID was listed as 1. (Can't kill init without rebooting). I, as root, issued a reboot command and also a shutdown now. I went through the list of running processes and manually killed every single process most became <defunct>. The system has a RAID 5 without a battery backup -- so I don't like yanking the cord out of the UPS, but this is what I ended up having to do.
Is there something else I should've tried? Some other command to run? It was using 100% of the CPU, and I need to finish my dissertation, so I just forcibly turned off the computer, but if it happens again, I'd like to be prepared. Note: I also renice'd the process to 19 and it 'took' -- i.e. it responded that the process was now at nice 19 and was at nice 0. However, it was still using 100% of the cpu.
Background: A friend was using the computer, so I haven't yet cycled through the history to see if there was anything malicious, but it crashed when he started firefox and it returned to ESPN's fantasy baseball website -- not a place I would expect flash malware to grow... Any thoughts?
You could try the SysRq method: http://en.wikipedia.org/wiki/Magic_SysRq_key#.22Raising_Elephants.22_mnemonic_device
You want to run them in a certain order as described in the wiki article: R E I S U B