Why does a kernel thread have a PID? [duplicate]

Question

In Linux, a kernel thread have a PID:

Why is that? Is a kernel thread considered to be a process? And does a "normal" thread also have a PID?

opensourceforu.com/2011/08/… should help
– Munir
Jun 20, 2017 at 0:56 — Munir, Jun 20, 2017 at 0:56
See also unix.stackexchange.com/questions/31595/…
– Anthony Geoghegan
Jun 20, 2017 at 9:09 — Anthony Geoghegan, Jun 20, 2017 at 9:09

alzee · Accepted Answer · 2017-06-20 00:36:27Z

6

They are poorly named. Kernel threads in linux are processes (not actual threads) that run in kernel space rather than user space.

answered Jun 20, 2017 at 0:26

alzee

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A process have many threads, does a kernel thread have many threads also?
– paul
Jun 20, 2017 at 2:55
@paul Related: stackoverflow.com/q/34959506/4941495
– Kusalananda ♦
Jun 20, 2017 at 6:09
1

Kernel threads do not run in their own address space. Since the usual definition of a thread (vs. a process) is that related threads are executed in a shared address space, I think thread is a more appropriate term than process here.
– Johan Myréen
Jun 20, 2017 at 7:08
@Johan Myréen A kernel thread has a PID as I have shown, but does a "normal" thread also have a PID?
– paul
Jun 20, 2017 at 18:19
@paul - "Normal" thread too has a PID, which is inherited from the creator process/thread (the one that called pthread_create() to launch it).
– FooF
Apr 27, 2020 at 8:29

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