Panic: double panic and "IPv4 address: "a.b.c.d" is not on the network" flood in current

I've just been forced to rollback from 9-CURRENT kernel to 8-BETA2 
kernel due to panics like this:

    Fatal double fault:
    eip = 0x808ddcec
    esp = 0xc7977fc0
    ebp = 0xc7978038

Dump header from device /dev/ad0s1b

      Architecture: i386
      Architecture Version: 2
      Dump Length: 446615552B (425 MB)
      Blocksize: 512
      Dumptime: Wed Aug 26 12:13:22 2009
      Hostname: serwer.obsysa.net
      Magic: FreeBSD Kernel Dump
      Version String: FreeBSD 9.0-CURRENT #0: Mon Aug 24 10:45:04 CEST 2009
        ncpnc_at_serwer.obsysa.net:/usr/obj/usr/src/sys/ATHLON9
      Panic String: double fault
      Dump Parity: 4040556634
      Bounds: 11
      Dump Status: good

Panic seems to be ZFS (or general FS)  related, as it happens with heavy 
IO, like during scrub or csup.
My kernel was built without debugging options so here's what I could 
provide:

    dmesg.boot (from 8-BETA2):
    http://obsysa.net/bsd/dmesg.boot

    kernel config:
    http://obsysa.net/bsd/ATHLON9

    vmcore (111MB!):
    http://obsysa.net/bsd/vmcore.11.bz2

I also noticed dmesg flood with messages like this:

    IPv4 address: "78.8.144.1" is not on the network

I have tun device which is used to connect to ADSL line via PPPoE:

    tun0: flags=8051<UP,POINTOPOINT,RUNNING,MULTICAST> metric 0 mtu 1492
            inet 78.8.144.74 --> 78.8.144.1 netmask 0xffffffff
            Opened by PID 443

So I guess it's PPP issue, and seems to be harmless for now...

-- 
Bartosz Stec