when we use “top -c” in Linux, which type of process is closed by brackets?

Question

As the title said, which type of process is closed by brackets?

Answer 1

Processes with names like ...

    2 ?        S      0:00 [kthreadd]
 1174 ?        S      9:13 [kjournald]
 1984 ?        S      2:43 [flush-202:0]

... are kernel threads. They can be distinguished from normal processes in that they typically show up with no memory usage.

Answer 2

processes in brackets [] are kernel threads...or processes that were started by init process...