Hi Mulyadi, On Thu, Jan 19, 2012 at 2:16 PM, Mulyadi Santosa <mulyadi.santosa@gmail.com>wrote:
Hi Darshan :)
On Thu, Jan 19, 2012 at 14:03, Darshan Ghumare <darshan.ghumare@gmail.com> wrote:
Hi Mulyadi,
How SIGKILL is handle by Kernel? Does SIGKILL & SIGTSTP handled separately than the rest of the signals?
I hope you don't mind if I cc this answer to kernelnewbies as well. Hopefully you will get better answer.
No.
Well, SIGKILL is handled like other usual signal. The important point to notice is that sigkill is handled entirely in kernel space. What it means is that it cannot be overriden in user space (i.e installing your own signal handler).
SIGKILL will tell the target process to terminate itself. So it pretty much will flow like normal process termination. However, the termination will be a bit rough. It will just kill....no time to wait for in flight I/O whatsoever.
What if, there is one process which is in middle of a syscall which has infinite loop in it received SIGKILL & there are no other processes in the system?
SIGSTOP...ehm, I think that is handled in kernel space too. The handler will basically move the process out of from run queue to the process stopped queue (or something like that, I forgot). Then it switch the process state from "running" to "stop". It's not the same like "sleep" btw.
Hope it helps....
-- regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com