Badness seen on 2.6.26-rc2 with lockdep enabled

I see the following error on my power box at boot up.

RTAS: event: 14, Type: Platform Error, Severity: 2

------------[ cut here ]------------
Badness at kernel/lockdep.c:2680
NIP: c0000000000ae538 LR: c0000000000ae51c CTR: 0000000000000000
REGS: c0000000e7b139a0 TRAP: 0700   Not tainted  (2.6.26-rc2-mm1)
MSR: 8000000000029032 <EE,ME,IR,DR>  CR: 24000042  XER: 20000000

TASK = c0000000e7644620[411] 'rtasd' THREAD: c0000000e7b10000 CPU: 1
GPR00: 0000000000000000 c0000000e7b13c20 c000000000a55ef0 0000000000000001
GPR04: 0000000000000001 c00000000004bfb8 2d37313000000000 2d37313031303438
GPR08: 3644442000000000 c000000000ea3018 0000000000000020 0000000000000001
GPR12: 3644442000000000 c000000000a94600 0000000000000000 0000000000000000
GPR16: 0000000000000000 0000000000000000 4000000001c00000 c00000000086f400
GPR20: 0000000000000000 0000000000000001 00000000000000e4 000000000246f400
GPR24: c000000000a9c498 0000000000000008 c00000000004bfb8 c00000000087a5d8
GPR28: c00000000092cd48 0000000000000001 c0000000009bb738 c0000000e7b13c20 NIP [c0000000000ae538] .check_flags+0x9c/0x174
LR [c0000000000ae51c] .check_flags+0x80/0x174

Call Trace:
[c0000000e7b13c20] [c00000000004bc70] .pSeries_log_error+0x5c/0x400 (unreliable)
[c0000000e7b13ca0] [c0000000000b35c0] .lock_release+0x80/0x204
[c0000000e7b13d50] [c0000000005cfcf8] ._spin_unlock_irqrestore+0x34/0x94
[c0000000e7b13de0] [c00000000004bfb8] .pSeries_log_error+0x3a4/0x400
[c0000000e7b13ef0] [c00000000004c218] .rtasd+0x98/0x100
[c0000000e7b13f90] [c00000000002848c] .kernel_thread+0x4c/0x68

Instruction dump:
e92d01b0 8009085c 2f800000 40be002c 481f1b9d 60000000 2fa30000 419e00c4 e93e80f8 80090000 2f800000 409e00b4 <0fe00000> 480000ac 78290464 80090014 possible reason: unannotated irqs-on.

irq event stamp: 30
hardirqs last  enabled at (29): [<c0000000000b1d98>] .trace_hardirqs_on+0x1c/0x3
0
hardirqs last disabled at (30): [<c0000000000aebac>] .trace_hardirqs_off+0x1c/0x
30
softirqs last  enabled at (28): [<c00000000008bd08>] .__do_softirq+0x180/0x1a8
softirqs last disabled at (21): [<c000000000028124>] .call_do_softirq+0x14/0x24

	Warm Regards,
	Balbir Singh
	Linux Technology Center
	IBM, ISTL

Could be RTAS playing with interrupt enabling without proper lockdep notifications. I'll have a look when I'm back.