New: Kernel panic after adding tap interface to bridge

http://bugzilla.kernel.org/show_bug.cgi?id=13129

           Summary: Kernel panic after adding tap interface to bridge
           Product: Networking
           Version: 2.5
    Kernel Version: 2.6.27.21
          Platform: All
        OS/Version: Linux
              Tree: Fedora
            Status: NEW
          Severity: normal
          Priority: P1
         Component: Other
        AssignedTo: [email protected]
        ReportedBy: [email protected]
        Regression: No

Created an attachment (id=21029)
--> (http://bugzilla.kernel.org/attachment.cgi?id=21029)
serial output after kernel panic

Box has a 1 active truncated Ethernet link with dozens VLANs. During system startup virtual interfaces are created to separate each VLAN data from the others'. Several brigdes sit on the top of them, one for each VLAN. Everything works fine until I try to add kvm linux guest to whichever VLAN brigde. Then kernel freezes in a few seconds.

Steps to reproduce:

1) configure network interfaces accordingly to what has been described above (standard RedHat/Fedora config files in /etc/sysconfig/network-scripts suffice).
2) create TAP device using tunctl
3) change the state of the device to up
4) add it to one of the bridges
5) run guest machine with one interface paired with previously created TAP device

Steps 2-4 can be handled automatically by qemu-kvm running script like this one:

#!/bin/sh

# prep_script.sh
set -x

switch=br100

if [ -n "$1" ];then
/usr/sbin/tunctl -p -t $1
/sbin/ip link set $1 up
sleep 0.5s
/usr/sbin/brctl addif $switch $1
exit 0
else
echo "Error: no interface specified"
exit 1
fi

Then guest can be fired up using the following command:

qemu-kvm -m 1024 -net nic,model=e1000 -net tap,script=/path/to/prep_script.sh /path/to/disk.img

Additional info:

Host: Fedora 10 (see kernel ring buffer output file and kernel config file)
Guest: CentOS 5.3