ipfw: switching sets does stall the machine

[Peter]

On Fri, Jun 14, 2019 at 10:21:52AM -0700, Freddie Cash wrote:

! > Details:
! > Machine : i386
! > OS      : FreeBSD 11.2-RELEASE-p10
! > Command : ipfw set disable 1 2 3 4 5 6 7 8 9 10 11 12 13 14 enable 16
! >                 17 18 19 20 21 22 23 24 25 26 27 28 29
! >
! 
! Can't speak to this specific lockup, but I'm curious to know if it works
! when you enable first, then disable (it's how we've used sets here at work).

Tried that already, it doesn't make a difference. And since
the operation is said to be atomically, it should not make a
difference.

But now I have an idea what might be the actual issue. One more try
for proof, and I send this message out first as otherwise it will be lost...