From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686) Gecko/20040107 Galeon/1.3.7

Description of problem:
When setting up an ethernet bridge between an Intel ethernet adapter
and a TUN/TAP device, the kernel locks up after a short while.

Version-Release number of selected component (if applicable):
kernel-2.4.20-28.9

How reproducible:
Always

Steps to Reproduce:
1  Create tap0 (e.g. run usermode-linux with --eth0=tuntap)
2. # ifconfig eth0 0.0.0.0 promisc up
3. # ifconfig tap0 0.0.0.0 promisc up
4. # brctl addbr br0
5. # brctl addif br0 eth0
6. # brctl addif br0 tap0
7. # ifconfig br0 192.168.0.1
8. # ping 192.168.0.2

Actual Results:  Hard lockup after a short while, Sys-Rq not possible,
nothing in logs.

Expected Results:  No lockup.

Additional info:

No problems with vanilla kernel 2.4.24.

eth0 driver is e100.
lspci info:
05:08.0 Ethernet controller: Intel Corp. 82801BD PRO/100 VE (LOM)
Ethernet Controller (rev 81)
        Subsystem: Compaq Computer Corporation: Unknown device 0091
        Flags: bus master, medium devsel, latency 66, IRQ 5
        Memory at fc500000 (32-bit, non-prefetchable) [size=4K]
        I/O ports at 1000 [size=64]
        Capabilities: [dc] Power Management version 2