Just today I find I have about 7 clusters of processes comprising groups of "cpuhp<digit>, migration/<digit>, ksoftirqd<digit>, kworker<digit>, kworker<digit>-kblockd" and I have no idea how to control this, which I suspect is totally useless behaviour just to use free cpu time. It's very distracting as it makes a noise, too. It never used to do it.

• cpuhp3
• migration/3
• ksoftirqd/3
• kworker/3
• kworker/3-kblockd

How can I stop it?

I guess that these are background processes open a terminal and "ps" command to confirm that.

Try killing them see "man kill" or "info kill" for details.

No, that looks like CPU hot-plug gone nuts - and I certainly wouldn't expect kill to work on (those) kernel threads.

What has changed ?. Did you do a system update that may have brought in a new kernel or function ?. If so try booting the prior kernel.
Have you recently installed something like KVM or virtualbox ?.

You may find this thread informative: https://www.linuxquestions.org/quest...er-4175563563/

I guess that it is still the same after a reboot? Ctl Alt F2 login and sudo shutdown -r now if it is stuck. Regards Ian

I can't even boot into that kernel now: I get kernel panic, VFS can't mount file system on unknown block (8, 20) and then sched complains about unknown CPU0 being rescheduled. When I get the can't sync message I usually boot into an older kernel and mount the newer partition and then it works when I reboot. Not any more, so I guess I'll try xfs-repair and if that works, I better recompile the kernel.
Hopefully I can thus solve both the failure to sync on boot problem and the unwanted spawn of kworker processes but at this stage any suggestions would be kindly regarded.

Sounds like you have been the instigator of this problem. That being the case it's hard for us to advise, except maybe diff the .config's and investigate.

Thanks to syg00 and others for replies

Normally by the time I write something it logs me out and I can't be bothered typing it all again, so I might not use this forum any more

Moved: This thread is more suitable in <Linux - Kernel> and has been moved accordingly to help your thread/question get the exposure it deserves.

Just for the record what distro are you using? I am on LinuxMint 18.3 and it is great. Regards Ian.