port-macppc/50338: panic with ping -f and rtk0

[scole_mail%gmx.com@localhost]

>Number:         50338
>Category:       port-macppc
>Synopsis:       panic with ping -f and rtk0
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    port-macppc-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Oct 16 20:20:00 +0000 2015
>Originator:     scole_mail
>Release:        7.0
>Organization:
none
>Environment:
NetBSD pm7200 7.99.21 NetBSD 7.99.21 (GENERIC-$Revision: 1.7 $) #1: Sat Oct 10 11:41:23 EDT 2015 scole@dstar:/home/scole/nbsd/src/sys/arch/macppc/compile/obj/GENERIC_601 macppc
>Description:
I'm getting a panic which I think is caused by high network activity:

trap: pid 590.1 (syslogd): kernel PGM trap @ 0x445c40 (SRR1=0x81030)
panic: trap
cpu0: Begin traceback...
0x00469f40: at vpanic+0x138
0x00469f70: at panic+0x4c
0x00469fb0: at trap+0x444
0x0046a030: kernel PGM trap by cpu_info+0: srr1=0x81030
           r1=0 cr=0x6f128 xer=0 ctr=0x1c6ca4 mq=0x6d40
cpu0: End traceback...
dumpsys: TBD
rebooting

This happens on current and 7.0.  I added a pci rtk0 card to my ppc601 machine to try to use it instead of the slower built-in mc0. 

I put both interfaces on the same network:
ifconfig_mc0="inet 10.0.0.19 netmask 255.255.255.0"
ifconfig_rtk0="inet 10.0.0.20 netmask 255.255.255.0"

"ping -f 10.0.0.20" (rtk) will load and eventually crash the machine.  Pinging the mc0 interface doesn't seem to cause a crash.

When both interfaces were up, with "netstat -i" I noticed pings would go in the mc0 but come out rtk0.  But pinging mc0 with or without rtk0 didn't seem to cause issues.  Pinging rtk0 caused the panic whether mc0 was up or not.

I think it also crashed once when doing a cvs update.
>How-To-Repeat:
add rtk interface and flood ping the machine.  
>Fix: