On Tue, Jul 03, 2007 at 09:15:01PM +0000, rthille@thille.org wrote:
> 	Kernel panic running 'perl' (probably running qpsmtpd)
> 	output on serial console:
> 	    trap: address error (load or I-fetch) in kernel mode
> 	    status=0x7c03, cause=0x10, epc=0x8002e110, vaddr=0x8452e672
> 	    pid=11628 cmd=perl usp=0x7fffdae0 ksp=0xcc85fc48
> 	    Stopped in pid 11628.1 (perl) at        netbsd:tcp_sack_option+0x110:   lw      a
> 	    0,0(s1)

I think your problem is decribed in PR 34751 and should be fixed already.
Try a 4.0_BETA2 kernel.