usbserial and ftdi

Has anyone here tried to get the ftdi_sio.ko and usbserial.ko drivers to work? I can build them against either 2.6.25 or 2.6.27.4, and they load into the kernel fine, but in both cases, when I plug in an ftdi USB device, I get a crash:

usb 1-1: new full speed USB device using at91_ohci a2
usb 1-1: configuration #1 chosen from 1 choice
Unable to handle kernel NULL pointer dereference at virtual address 00000088
pgd = c0004000
[00000088] *pgd=00000000
Internal error: Oops: 17 [#1]
Modules linked in: ftdi_sio usbserial
CPU: 0 Not tainted (2.6.27.4 #3)
PC is at kref_get+0x10/0x50
LR is at kobject_get+0x20/0x28
pc : [<c0143ec0>] lr : [<c014318c>] psr: 20000013
sp : c1c7bb78 ip : c1c7bb90 fp : c1c7bb8c
r10: 00000000 r9 : 00000000 r8 : bf014634
r7 : c1d5e540 r6 : bf01200c r5 : bf0068d0 r4 : 0000006c
r3 : 00000000 r2 : 00000000 r1 : ffffffa4 r0 : 00000088
Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 0005317f Table: 21dd0000 DAC: 00000017
Process khubd (pid: 62, stack limit = 0xc1c7a268)
Stack: (0xc1c7bb78 to 0xc1c7c000)
bb60: bf01200c 0000006c
bb80: c1c7bba4 c1c7bb90 c014318c c0143ec0 c019e0e0 ffffffa4 c1c7bbb4 c1c7bba8
bba0: c016cc9c c014317c c1c7bbcc c1c7bbb8 c0196248 c016cc90 bf01200c 00000000
bbc0: c1c7bca4 c1c7bbd0 bf0013e4 c0196238 c1dac400 c01422d0 ffffffa4 000007c0
bbe0: c00c35a0 c1e0a188 c1c0ee00 c1e0a188 00000001 00000000 c1c7bc1c c1c7bc08
bc00: c1c7bc5c c1c7bc10 c00c3ca4 c0236f78 c1e0ab48 c1c7bc28 c1c7bc44 c1c7bc28
bc20: c00c39d8 c00c38a4 c00c3b38 c1e0ab48 c1e0a428 00000000 c1e0a428 c1c7bc60
bc40: c1e0a188 00000001 00000000 00000000 c1c7bc94 c1c7bc60 c00c49f0 c00c3c98
bc60: c1c7bc8c c1c7bc70 c019e0fc c019e000 c019e0fc bf01200c c1dac400 c1dac400
bc80: bf0145cc bf01200c c1d86400 c02dfe34 00000000 00000000 c1c7bcc4 c1c7bca8
bca0: c019f1f8 bf001304 c1dac420 c016f7fc bf0145fc c1c7bcfc c1c7bce4 c1c7bcc8
bcc0: c016f6d4 c019f114 00000000 c016f7fc c1dac420 c1c7bcfc c1c7bcf4 c1c7bce8
bce0: c016f80c c016f60c c1c7bd24 c1c7bcf8 c016ea28 c016f80c 000000d0 c1c34628
bd00: c1c34628 c1d5e154 c1dac420 c1dac420 c1dac4cc c1dac4ac c1c7bd44 c1c7bd28
bd20: c016f898 c016e9e0 c1dac420 c02dfe50 c1dac420 00000000 c1c7bd5c c1c7bd48
bd40: c016e854 c016f84c c1dac400 c1dac420 c1c7bda4 c1c7bd60 c016d684 c016e834
bd60: c1d86460 c1dac488 c1e09420 00000000 c1c7bd98 c1c7bd80 c016c708 c1dac400
bd80: c1dac400 c1d86460 00000000 c1d864ec c1e09420 00000000 c1c7be14 c1c7bda8
bda0: c019d708 c016d2c8 00000001 00000000 00000000 00000000 00001388 c1c7bdc8
bdc0: c1d86404 c1d864ec c1d86460 00000001 c1daca00 c1d807e0 00000001 c1daca04
bde0: c1daca00 00000001 c1d864ec c1d86400 00000001 c02e0428 c1c7be84 c02dfcd8
be00: 00000000 c1d5ac00 c1c7be3c c1c7be18 c01a4e10 c019d294 c00c4aac c00c491c
be20: c1c7be4c c1d86460 c016f7fc c02e0428 c1c7be4c c1c7be40 c019f080 c01a4dcc
be40: c1c7be6c c1c7be50 c016f6d4 c019f050 00000000 c016f7fc c1d86460 c1c7be84
be60: c1c7be7c c1c7be70 c016f80c c016f60c c1c7beac c1c7be80 c016ea28 c016f80c
be80: 000000d0 c1c34628 c1c34628 c1c69ab4 c1d86460 86460 c1d8650c c1d864ec
bea0: c1c7becc c1c7beb0 c016f898 c016e9e0 c1d86460 c2dfe50 c1d86460 00000000
bec0: c1c7bee4 c1c7bed0854 c016f84c c1c7bef1 c1d86460 c1c7bf2c c1c7bee8
bee0: c016d684 c0161d5ac60 c1d864c8 39383174 c000313a c1d86400 00000000
bf00: c1c3ed40 c1d860 c1d86460 00000000 00000002 c1d2f000 00000001 c1d5ac00
bf20: c1c7bf4c c1c7bf30 c019821c c016d2c8 c1d2f014 00000000 c1d86400 c1c3ed40
bf40: c1c7bfd4 c1c7bf50 c0199770 c01981dc c1c7bf74 c1c1c01c c1c7bf94 c1d5ac00
bf60: c1c7a000 c1d08220 c1d5ac00 00000001 c1d2f000 00000000 c1d08220 00000012
bf80: 00000000000 00000000 c1c633e0 c00508a8 c1c7bf94 c1c7bf94 0000011
bfa0: 01010001 c0039974 c1c7bfd4 c1c7a000 00000000 c0198fa8 00000000000
bfc0: 00000000 00000000 c1c7bff4 c1c7bfd8 c005057c0198fb8 00000000 00000000
bfe0: 00000000 00000000 00000000 c1c7bff8 c003fa5c c0050530 00000000 00000000
Backtrace:
[<c0143eb0>] (kref_get+0x0/0x50) from [<c014318c>] (kobject_get+0x20/0x28)
r4:0000006c
[<c014316c>] (kobject_get+0x0/0x28) from [<c016cc9c>] (get_device+0x1c/0x24)
r4:ffffffa4
[<c016cc80>] (get_d0/0x24) from [<c0196248>] (usb_get_dev+0x20/0x28)
[<c0196228>] (usb_v+0x0/0x28) from [<bf0013e4>] (usb_serial_probe+0xf0/0xd9 [us)
00000000
[<bf0012f4>] (usb_serial_probe+0x0/0xd9c [usbsial]) from [<c019f1f8>] (usb_prob8
r7:c1c7bcfc r6:bf0145fc r5:c016f7fc r4:c1dac420
[<c016ffc>] (driver_probe_device+0x0/0x18c) from [<c016_device_attach+0x10/0x14)
r7:c1c7bcfc r6:c1dac420 r5:c016f7fc r4:00000000
[<c016f7fc>] (__device_attach+0x0/0x14) from [<c016(bus_for_each_drvx58/0x98)
[<c016e9d0>] (bus_for_each_drv+0x0/0x98) from c016f898>] (device_attach+0x5c/0x)
r7:c1dac4ac r6:c4cc r5:c1dac420 r4:c1dac420
[<c016f83c>] (device_attach+0x0/0x7c016e854>] (bus_attach_device+0x30/0x64)
r6:00000000 r5:c1dac420 r4:c02dfe50
[<c016e824>] (bus_attach_device+0x0/0x64) from 684>] (device_add+0x3cc/0x54c)
r5:c1dac420 r4:c1dac400
[<c016d2b8>] (de_add+0x0/0x54c) from [<c019d708>] (usb_set_configuratix484/0x51)
[<c019d284>] (usb_set_configuration+0x0/0x514) from [<>] (generic_probe+0x54/0x)
[<c01a4dbc>] (generic_probe+0x0/0x98) from [<c019f080>] (usb_probe_device+0x40/)
r6:c02e06f7fc r4:c1d86460
[<c019f040>] (usb_probe_device+0x0/0x48) from [<c01] (driver_probe_device+0xd8/)
[<c016f5fc>] (driver_probe_device+0x0/0xc) from [<c016f80] (__device_attachx10/)
r7be84 r6:c1d86460 r5:c016f7fc r4:00000000
016e9d0>] (bus_for_each_drv+0x0/0x98) from [<c016f898>] (device_attach+0x74)/0x)
r7:c1d864ec r6:c1d8650c r5:c1d86460 r4:c1d86460
016f83c>] (device_attach+0x0/0x74) from [<c016e854>] (bus_attach_de0/0x64)
r6:00000000 r5:c1d86460 r4:c02dfe50
[<c016e824>] (bus_attach_de+0x0/0x64) from [<c016d684>] (device_add+0x3cc/0x54r1
[<c016d2b8>] (device_add+0x0/0x54c) from [<cc>] (usb_new_device+0x50/0x9c)
[<c01981cc>] (usb_new_device+0x0/0x9c) from [<c0199770>] (hub_thread+0x7c8/0xc7)
r6:c1c31d86400 r4:00000000
[<c0198fa8>] (hub_thread+0x0/0xc74) from [<c00505kthread+0x5c/0x94)[<c0050520>])
r6:00000000 r5:00000000 r4:00000000
Coa0c00d e92dd810 e24cb004 e24dd004 (e5903000)
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