In the Known Problems document for 3.1.12 release, you mention an issue with the Xircom Cardbus card is shut down. I 'm not sure if this is exactly the same, but am able to reproduce an oops when removing the card while the tulip_cb module is loaded under kernel 2.3.51.
If rtnetlink messages are configured, the unregister_netdevice() call from the tulip_cb 'remove' operation kicks rtnetlink into issuing a routing message via the notifier block. This seems to be happening under interrupt (or at least, in_interrupt() returns true), which results in an oops as rtnetlink tries to allocate an skb non-atmomically.
There seem to be a number of other issues including tx timeouts. Unfortunately, I don't know enough about PC hardware to take this much further, but have noticed that tulip_cb registers itself as a pci driver. Is this correct?
Also, the non-pcmcia tulip driver in the current tree seems to be undergoing some significant changes. Is the pcmcia version being maintained in sync with this?