Hi,
I got this oops on 2.6.24-rc1-641-gb4f5550:
[18073.371126] Unable to handle kernel NULL pointer dereference at 0000000000000120 RIP:
[18073.371134] [<ffffffff8023572e>] check_preempt_wakeup+0x6e/0x110
[18073.371144] PGD 81f9067 PUD 81c8067 PMD 0
[18073.371151] Oops: 0000 [1] PREEMPT SMP
[18073.371157] CPU 2
[18073.371161] Modules linked in: vfat fat
[18073.371168] Pid: 4639, comm: kwin Not tainted 2.6.24-rc1 #1
[18073.371171] RIP: 0010:[<ffffffff8023572e>] [<ffffffff8023572e>] check_preempt_wakeup+0x6e/0x110
[18073.371177] RSP: 0018:ffff810008531a78 EFLAGS: 00010006
[18073.371179] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
[18073.371183] RDX: ffff810004441bf0 RSI: ffff81000801e860 RDI: ffff81000444ab80
[18073.371186] RBP: ffff810008531aa8 R08: 000000d0d47a4a90 R09: 0000000000000000
[18073.371188] R10: ffff810004441bf0 R11: 0000000000000001 R12: ffff810006520400
[18073.371190] R13: ffff81000801e860 R14: ffff81000a63a000 R15: ffff81000443d8e0
[18073.371193] FS: 00002b7d646a86f0(0000) GS:ffff810004c11780(0000) knlGS:0000000000000000
[18073.371196] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[18073.371199] CR2: 0000000000000120 CR3: 0000000008495000 CR4: 00000000000006e0
[18073.371202] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[18073.371211] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[18073.371214] Process kwin (pid: 4639, threadinfo ffff810008530000, task ffff81000840a860)
[18073.371216] Stack: ffff81000444ab80 0000000000000001 ffff81000801e860 ffff81000444ab80
[18073.371231] 0000000000000002 ffff81000443d8e0 ffff810008531b38 ffffffff8023061e
[18073.371238] 0000000000000000 ffff810004441b80 0000000000000002 0000000100000000
[18073.371245] Call Trace:
[18073.371250] [<ffffffff8023061e>] try_to_wake_up+0x2fe/0x3a0
[18073.371253] [<ffffffff802306cd>] default_wake_function+0xd/0x10
[18073.371257] [<ffffffff8022daca>] __wake_up_common+0x5a/0x90
[18073.371260] [<ffffffff8023095a>] ...
