Carlos E. R. wrote:
On 20/03/2020 20.55, Dave Howorth wrote:
On Fri, 20 Mar 2020 19:58:44 +0100 Per Jessen <per@computer.org> wrote:
Carlos E. R. wrote:
On 20/03/2020 16.25, Dave Howorth wrote:
On Fri, 20 Mar 2020 13:21:17 +0100 Per Jessen <> wrote:
Carlos E. R. wrote:
> Sorry, I still do not understand why a user process such as mc > can not be destroyed on order. No excuses.
A user process can enter kernel mode - this one did, and then disabled interrupts. I.e. it has to complete.
Disabled interrupts? But all the processes were working, only this one was stuck. My training said that when interrupts were disabled, noone got access to them.
I don't understand a word of that ?
When one process blocks interrupts, my teachers told me it applied to the entire computer, all processes. Nothing, not even the kernel, can intervene. The keyboard gets blocked, the clock interrupts gets blocked.
Interrupts are blocked per process. Very basic example: I might have a daemon I want to ignore Ctrl-C (SIGINT), so I block it. Does not mean any other process should also ignore it.
It is impossible to block interrupts for minutes
It is entirely possible to block interrupts for minutes.
I also do not understand how a user process can block interrupts, that should be reserved to the kernel.
Because it was in kernel mode, probably in a kernel driver. In your case, maybe some filesystem code. A user process does not always remain in user mode, it needs services from the kernel, for instance to do I/O. -- Per Jessen, Zürich (10.7°C) http://www.hostsuisse.com/ - virtual servers, made in Switzerland. -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org