I can not kill
kill -9 or
pkill -f -9.
Does anyone how to kill or stop those process?
(I am using Ubuntu 16.04, if that is relevant.)
As @hobbs explained, it is a kernel thread. A broader perspective is the following:
IRQ handling is problematic in any OS because interrupts can arrive at any time. Interrupts can arrive even while the kernel is in the middle of working on a complex task and resources are inconsistent (pointers are pointing to invalid addresses and so on). This problem can be solved with locks, i.e. don't allow the interrupt handlers to run until the kernel is in an interruptible, consistent state. The disadvantage of using locks is that too many locks make the system slow and inefficient.
Thus, the optimal solution for the problem is this:
These "background" threads are the interrupt handler kernel threads.
top as normal processes.
They are essentially kernel threads running in the background.
You can't kill kernel threads: they are managed entirely by the kernel. If you could kill it, the irq/142 handler in your nvidia driver wouldn't exist any more: if your video card sends an interrupt, nothing would handle it. The result would be likely a freeze, but your video surely wouldn't work any more.
The problem in your system is that this interrupt handler gets a lot of CPU resource. There are many potential reasons:
Knowing the quality of the Nvidia drivers, unfortunately a buggy driver is the most likely.
The solution is to somehow reset this driver. Some ideas, ordered ascending by brutality:
If you kill X and you still see this kernel thread, you may try to remove the Nvidia kernel module (you can see it in the list given by
lsmod, then you can remove it with
rmmod). Restarting X will
insmod it automatically, resetting the hardware.
If none of these work, you need to reboot. If an ordinary reboot doesn't work you can do this with additional brutality: use alt/printscreen/s followed by alt/printscreen/b.
Extension: as a temporary workaround you could try to give a very low priority to that thread (
renice +20 -p 1135). Then it will still run, but it will have less impact on your system performance.
You've probably been hacked and they are running spambots, tradingbots or even mining. Get in firewall the crap out of it, change root password, deinstall any instance of Openssh and upgrade the kernel. I just moved up to the next release.
Be sure to block outgoing ssh. Then watch the ufw.log as the peers try to connect (list of other hacked nodes in the network). Note the list of repositories when running the upgrade. You are likely to note your desktop's 'username'-files as a subdomain listed. Because they tar balled and ex-filtrated your workstation's files when you connected.
Then dig in... I'm looking for the credentials to kill the repository.