> Hi,
>
> On Fri, 09 Oct 1998 09:59:53 -0500, Steven Suson
> <suson@tti.TuckerEnergy.com> said:
>
> > It seems that at some point between 2.1.98 and 2.1.123, the queue
> > used for POSIX signals went from a purely dynamic model (limited by
> > memory considerations) to a static model (currently 1024). I would very
> > much like to know why?
>
> Because queued signals take up privileged, unswappable kernel memory,
> and if you don't limit them, then any user can allocate unbounded memory
> by sending blocked signals. It's a very effective denial-of-service
> attack!
>
> > what about the possibility of reverting to the dynamic model? If this
> > isn't feasible, is it possible to increase the limit from 1024, and if
> > so, what would be the maximum?
>
> You should be able to set it to any level you want. The patch below
> makes both the current number of queued signals and the upper limit
> available through the sysctl and /proc/sys/kernel interfaces, and allows
> you to modify the limit.
>
> Linus, this also fixes a bug introduced in 2.1.124: somebody renumbered
> two of the existing sysctl tables _again_...
>
> --Stephen
>
Stephen,
Thanks so much for the quick solution. We will be looking to apply this
patch, and test it, within the next few days. Obviously, this gets our hearty
support for inclusion in the 2.2 kernel.
Thanks again,
Steve Suson
"Keep the faith."
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