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Re: kill (0, SIGSTOP) is freezing the system (was: /hurd/init and /hurd/
From: |
Justus Winter |
Subject: |
Re: kill (0, SIGSTOP) is freezing the system (was: /hurd/init and /hurd/proc) |
Date: |
Wed, 31 Jul 2013 11:50:55 +0200 |
User-agent: |
alot/0.3.4 |
Quoting Samuel Thibault (2013-07-29 13:36:33)
> Justus Winter, le Fri 26 Jul 2013 13:24:49 +0200, a écrit :
> > > > I'm not sure about how important it is not to freeze anyone of them,
> > > > but at least procfs must not be stopped b/c killall5 wants to
> > > > iterate over /proc.
> > >
> > > And /proc might not even be started yet, so exec need to be unfrozen at
> > > least, to start it. Perhaps killall5.c could have a Hurd-specific
> > > function to use libps to identify procfs and let it continue.
> > >
> > > > But it would surely be nice not to freeze filesystem translators, and
> > > > probably the pagers and the term translators.
> > >
> > > So should perhaps translators be marked as such and avoided?
> >
> > So you are saying that any translator started by root should be
> > considered essential?
>
> For instance, yes.
>
> > A more explicit variant would be to let translators set themself as
> > essential, would you prefer that?
>
> That should work too. I'd tend to prefer that.
Cool, will do.
> That said, we don't want to mix up "essential" as it happens to be now
> (whenever it crashes, init crashes the whole system) with "essential" as
> we want it to have (do not kill it on killall -1).
Good point. I've been consulting thesaur{i,uses} to find a synonym for
"essential". The best ones I found were
* crucial
* vital
* important (being a little weaker than essential, which might be
good)
* something more different like untouchable (protected, shielded,
immune)
Suggestions? Opinions?
Somewhat related, I was thinking not to deliver fatal signals to
*essential* (in the traditional /hurd/init way) servers, at least not
until there is a recovery/reincartation strategy for these servers. As
I understand POSIX this is okay, e. g. killing pid 1 is denied on most
systems (I think Linux just silently does nothing). Thoughts?
Justus
- kill (0, SIGSTOP) is freezing the system (was: /hurd/init and /hurd/proc), (continued)
- kill (0, SIGSTOP) is freezing the system (was: /hurd/init and /hurd/proc), Justus Winter, 2013/07/24
- [PATCH 2/7] hurd: add proc_mark_essential, Justus Winter, 2013/07/24
- [PATCH 1/7] proc: add proc_mark_essential server code, Justus Winter, 2013/07/24
- [PATCH 4/7] init: Build fixes, Justus Winter, 2013/07/24
- [PATCH 3/7] init: Mark auth, proc and fs servers as essential, Justus Winter, 2013/07/24
- [PATCH 6/7] proc: evil hack, mark all pids<100 essential, Justus Winter, 2013/07/24
- [PATCH 5/7] proc: Fix miscalculation of count, Justus Winter, 2013/07/24
- Re: kill (0, SIGSTOP) is freezing the system (was: /hurd/init and /hurd/proc), Samuel Thibault, 2013/07/24