required kernel rebuilds

[Eugene Grosbein]

13.09.2017 22:55, Michael W. Lucas пишет:
> Hi,
> 
> Book research question.
> 
> Way back in the Dark Ages of the 1990s, it wasn't uncommon to rebuild
> a kernel to fix a recurring panic. You'd have to tune MAXUSERS, or
> PMAP_SHPGPERPROC.
> 
> AFAIK, dang near everything is tunable in either loader.conf or
> sysctl.conf. I really want to say that kernel rebuilds for these kinds
> of limits aren't needed any more.
> 
> Does anyone have a counter-example, though? Is anything possibly
> crash-inducing non-tunable without a kernel rebuild?

Kernel stack overflow produce "double fault" panic and while
i386 and amd64 platforms have loader tunnable kern.kstack_pages to increase
this limit without need to rebuild the kernel, other platforms
still do not have such tunnable and have kernel config file "options KSTACK_PAGES" only.

See also https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219476 for details.