kern/50417: TCP_CHECKSUM panic()

[gergely%egervary.hu@localhost]

>Number:         50417
>Category:       kern
>Synopsis:       TCP_CHECKSUM panic()
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Nov 10 16:05:00 +0000 2015
>Originator:     Gergely EGERVARY
>Release:        NetBSD 6.1_STABLE
>Organization:
>Environment:
NetBSD galileo.poli.hu 6.1_STABLE NetBSD 6.1_STABLE (GALILEO) #7: Tue Nov 10 14:00:54 CET 2015  root%venus.poli.hu@localhost:/usr/src/sys/arch/amd64/compile/GALILEO amd64
>Description:
Compiling TCP_CHECKSUM into kernel, and starting a checksum-enabled TCP session (bgpd from quagga) panics kernel. It's 100% reproducible for me.

Is TCP_CHECKSUM known to be broken in 6.x?

---
panic: stack overflow detected: terminated
cpu0: Begin traceback...
printf_nolog() at netbsd:printf_nolog
ssp_init() at netbsd:ssp_init
tcp_output() at netbsd:tcp_output+0x1f90
tcp_usrreq() at netbsd:tcp_usrreq+0x3bd
tcp_usrreq_wrapper() at netbsd:tcp_usrreq_wrapper+-0x36b0
do_sys_connect() at netbsd:do_sys_connect+0x8d
sys_connect() at netbsd:sys_connect+0x38
syscall() at netbsd:syscall+0xc4
cpu0: End traceback...

>How-To-Repeat:
Compile TCP_CHECKSUM into kernel...

>Fix: