[origin tree boot crash] NULL pointer dereference, IP:[<ffffffff82b07130>] ibm_find_acpi_device+0x5c/0xf5

[Ingo Molnar]

> commit 15b8dd53f5ffaf8e2d9095c423f713423f576c0f
> Date:   Mon Jun 29 13:39:29 2009 +0800
> 
>     ACPICA: Major update for acpi_get_object_info external interface

this one is causing boot crashes in -tip testing:

acpiphp: ACPI Hot Plug PCI Controller Driver version: 0.5
initcall acpiphp_init+0x0/0x83 returned -19 after 16410 usecs
calling  ibm_acpiphp_init+0x0/0x190 @ 1
BUG: unable to handle kernel NULL pointer dereference at 0000000000000003
IP: [<ffffffff82b07130>] ibm_find_acpi_device+0x5c/0xf5
PGD 0 
Oops: 0002 [#1] SMP DEBUG_PAGEALLOC
last sysfs file: 
CPU 0 
Pid: 1, comm: swapper Not tainted 2.6.31-tip #16786 System Product Name
RIP: 0010:[<ffffffff82b07130>]  [<ffffffff82b07130>] ibm_find_acpi_device+0x5c/0xf5
RSP: 0018:ffff88003f2d1d60  EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88003f2d1d68 RSI: 00000000000001e4 RDI: 0000000000000000
RBP: ffff88003f2d1d90 R08: 0000000000000001 R09: ffffffff824b645b
R10: 000000002d0ef63b R11: ffff88003f2d1a80 R12: ffff88003fa780d0
R13: ffffffff83940dc8 R14: 0000000000000001 R15: ffffffff83942e10
FS:  0000000000000000(0000) GS:ffff880005800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 0000000000000003 CR3: 0000000001001000 CR4: 00000000000006b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 1, threadinfo ffff88003f2d0000, task ffff88003f2c8000)
Stack:
 ffff88003f2c8000 ffff88003cfbb690 000000002d0ef63b 0000000000000000
<0> 0000000000000000 ffff88003fa780d0 ffff88003f2d1e10 ffffffff8156b6b6
<0> 0000000000000001 0000000100000000 0000000000000000 ffffffff83940dc8
Call Trace:
 [<ffffffff8156b6b6>] acpi_ns_walk_namespace+0x11d/0x234
 [<ffffffff82b070d4>] ? ibm_find_acpi_device+0x0/0xf5
 [<ffffffff8157b159>] ? acpi_ut_acquire_mutex+0xd9/0x12e
 [<ffffffff82b070d4>] ? ibm_find_acpi_device+0x0/0xf5
 [<ffffffff81566dfa>] acpi_walk_namespace+0x105/0x162
 [<ffffffff81d067bf>] ? acpi_pm_read+0xd/0x3e
 [<ffffffff82b06f44>] ? ibm_acpiphp_init+0x0/0x190
 [<ffffffff82b06fa8>] ibm_acpiphp_init+0x64/0x190
 [<ffffffff810090b4>] do_one_initcall+0x82/0x1a6
 [<ffffffff810edecc>] ? init_irq_proc+0x77/0x9a
 [<ffffffff82ad8975>] do_basic_setup+0x5e/0x87
 [<ffffffff82ad8a26>] kernel_init+0x88/0xe2
 [<ffffffff8103ddfa>] child_rip+0xa/0x20
 [<ffffffff8103d7bc>] ? restore_args+0x0/0x30
 [<ffffffff82ad899e>] ? kernel_init+0x0/0xe2
 [<ffffffff8103ddf0>] ? child_rip+0x0/0x20
Code: 48 c7 c2 c0 7b 0b 82 48 c7 c6 95 39 4a 82 48 c7 c7 1a 3c 4a 82 31 c0 e8 02 84 4b ff 31 c0 e9 82 00 00 00 48 8b 45 d8 48 8b 40 30 <c6> 40 03 00 48 8b 45 d8 83 78 18 00 74 5f f6 40 0d 04 74 59 48 
RIP  [<ffffffff82b07130>] ibm_find_acpi_device+0x5c/0xf5
 RSP <ffff88003f2d1d60>
CR2: 0000000000000003
---[ end trace 5a5d197966b56a2e ]---
Kernel panic - not syncing: Fatal exception
Pid: 1, comm: swapper Tainted: G      D    2.6.31-tip #16786

This is a huge commit which doesnt revert cleanly. I took a stab at it, 
see that revert below - it didnt help.

Obviously we'd want a fix instead of that - i'm willing to test any 
patch.

oh. I should have looked at the crash site before bisecting and 
reverting. That sure looks like an unconverted acpi_get_object_info() 
call, right?

	Ingo

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