em0, VLAN and bpf(?) trouble w/RELENG_5

[Lenar D. Tukhvatullin]

I have similar problem (but with "bge" interface).
See PR: http://www.freebsd.org/cgi/query-pr.cgi?pr=72933
Can you recompile and test kernel with my patch?

--
Lenar D. Tukhvatullin

On Mon, Nov 08, 2004 at 03:45:18PM +0200, astesin at ukrtelecom.net wrote:
> Dear FreeBSD developers,
> 
> I'we run unto a big problem with RELENG_5, built at Thu Nov  4 15:07:44
> 2004.
> 
> Hardware is P-IV 3.0 (HTT off in BIOS), Intel S875WP1E motherboard, Promise
> SATA RAID onboard (1+0 setup, works fine), and 2 onboard LANs: em0 and fxp0.
> 
> em0 is in 802.11q VLAN trunk mode, connected to Cisco Catalyst 2950T. vlan0
> is configured on top of em0 and acts as an Internet connection of the box,
> it has a /30 IPv4 address block ("mini-ether") configured (2 addresses used,
> one is at vlan0, other is Cisco router on the other side).
> 
> The problem. From time to time, vlan0 stops passing packets at all. At this
> moments, Catalyst stops seeing MAC of vlan0 (it's the same MAC as em0) in
> the mantione VLAN (untagged VLAN is also configured at em0 and works fine!).
> This means that `show mac-address-table vlan XX' command on Catalyst don't
> show the MAC.
> 
> The problem can be easily repeated manually. It's enough just to issue a
> command like `trafshow -I vlan0' of `tcpdump -I vlan0' and voila! vlan0 is
> out of business, no packets are going through.
> 
> System is Ok at the same time, no panic, no freeze, just no packets through
> vlan0 that's it. Rebooting the box cures the problem (for some amount of
> time).
> 
> Am I doing something wrong? Or is this a bug somewhere? In 4.* vlans worked
> without a glitch...