panic: sbflush_internal: cc 4294966301 || mb 0 || mbcnt 0

[Bruce M. Simpson]

I was able to reproduce this bug, although the circumstances under which 
I did it are weird.

I have two NICs on the same box patched to the same Ethernet broadcast 
domain, but on interconnected switches with no spanning tree. If I stop 
VLAN_HWTAGGING on msk with a vlan interface attached, and then run ping 
-f to a local host via the network configured on fxp, it seems to 
trigger the problem.

sb_cc is always 84 bytes, which is 20 bytes IPv4 header + 64 bytes of 
ICMP data, so it's definitely ping which is triggering the issue in my 
case. I haven't been able to get a clean dump yet as my 6.2-RELEASE 
userland doesn't seem to understand -CURRENT's minidumps.
 
Hope this helps,
BMS