Re: limits.conf/stacksize doesn't seem to work?

From: Mehmet Erol Sanliturk <m.e.sanliturk_at_gmail.com>
Date: Sat, 16 Jul 2022 00:18:06 UTC 
On Sat, Jul 16, 2022 at 1:32 AM Mark Johnston <markj@freebsd.org> wrote:

> On Fri, Jul 15, 2022 at 05:26:09PM -0500, Larry Rosenman wrote:
> > On 07/15/2022 5:24 pm, Mark Johnston wrote:
> > > On Fri, Jul 15, 2022 at 05:21:27PM -0500, Larry Rosenman wrote:
> > >> On 07/15/2022 5:18 pm, Mark Johnston wrote:
> > >> > On Fri, Jul 15, 2022 at 05:04:18PM -0500, Larry Rosenman wrote:
> > >> >> I'm using the following kernel config:
> > >> >> [...]
> > >> >> and the following login.conf:
> > >> >> [...]
> > >> >> bacula_dir:\
> > >> >>         :stacksize-max=68719476736:\
> > >> >>         :stacksize-cur=68719476736:\
> > >> >>         :tc=daemon:
> > >> >> [...]
> > >> >> I've updated my (ler) password entry to reference bacula_dir:
> > >> >> ler:<elided>:1001:1001:bacula_dir:0:0:Larry
> > >> >> Rosenman:/home/ler:/usr/local/bin/zsh
> > >> >>
> > >> >>
> > >> >> when I ssh in, the stacklimit is still:
> > >> >> โฏ ulimit -H -s
> > >> >> 2097152
> > >> >
> > >> > What is the value of the kern.maxssiz sysctl on this system?
> > >> >
> > >> >> ler in ๐ŸŒ borg in sys/amd64/conf๐Ÿ”’ on ๎‚ 
> ler/freebsd-main-changes:main on
> > >> >> โ˜๏ธ  (us-east-1)
> > >> >> โฏ ulimit -S -s
> > >> >> 2097152
> > >> >>
> > >> >> ler in ๐ŸŒ borg in sys/amd64/conf๐Ÿ”’ on ๎‚ 
> ler/freebsd-main-changes:main on
> > >> >> โ˜๏ธ  (us-east-1)
> > >> >> โฏ
> > >> >>
> > >> >> Where does this number come from?  What am I missing here?
> > >> >
> > >> > The stack limit cannot be set to an arbitrarily large number.  It
> will
> > >> > silently be clamped to maxssiz.
> > >>
> > >> โฏ sysctl kern.maxssiz
> > >> kern.maxssiz: 2147483648
> > >
> > > Then what you're seeing is expected.  The kernel is clamping the stack
> > > segment limit to 2GB.
> >
> > I assume this is the default for MAXSSIZ?  and if I change that in the
> > kernel config, it will
> > allow bigger?  Where is this default defined?
>
> The default value is platform dependent.  On amd64 it's 512MB, so I'm
> not sure where your value is coming from.



-------------------------------------------------------



> It's defined in a header.
> You can set it in the kernel configuration, or as a tunable or sysctl.
>
>
-------------------------------------------------------


My opinion is that , there is some one ( or more ) constant(s)
defined elsewhere , because

setting  MAXSSIZ  is  NOT WORKING when it is larger than

the "unknown" default value ...


With my best wishes for all ,

Mehmet Erol Sanliturk