kern/53557: [patch]: kernel panic: fix for a divide by zero processor exception

[Bruce Evans]

On Fri, 20 Jun 2003, Christian S.J. Peron wrote:

> >Description:
> 	If root sets the kern.log_wakeups_per_second variable to 0
> 	the next time the callback for the syslog wakeup gets scheduled
> 	it will panic due to divide by zero machine exception.

Don't do that then.

There are hundreds or thousands of sysctls that may be used for much
more interesting foot shooting than a panic.  If foot shooting prevention
is required, then it should be implemented more generally starting
with simple range checks for all sysctls that set scalar values.

Bruce