Origin of a kworker-thread

Question

On my newly installed system using kernel 3.2 I see a kworker-thread which is constantly consuming CPU. I'd like to find out which part of kernel/module has created this workqueue. How to track a kworker-thread named for example ''kworker/0:3 to its origin in kernel-space? I tried to look into /sys/kernel/debug/tracing/events/workqueue, but wasn't able to figure it out.

Accepted Answer

(Seems to me this is rather off topic here, but here's the answer I posted on unix.stackexchange.com.)

I found this thread on lkml that answers your question a little. (It seems even Linus himself was puzzled as to how to find out the origin of those threads.)

Basically, there are two ways of doing this:

```
$ echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event
$ cat /sys/kernel/debug/tracing/trace_pipe > out.txt
(wait a few secs)
```

For this you will need ftrace to be compiled in your kernel.

This will output what threads are all doing, and is useful for tracing multiple small jobs.

```
cat /proc/THE_OFFENDING_KWORKER/stack
```

This will output the stack of a single thread doing a lot of work. It may allow you to find out what caused this specific thread to hog the CPU (for example). `THE_OFFENDING_KWORKER` is the pid of the kworker in the process list.

Origin of a kworker-thread

Solution

Problem