Re: 2.6.25-rc8-mm1 panic in rpaphp_register_slot()

[Alex Chiang <achiang@hp.com>]

* Badari Pulavarty <pbadari@us.ibm.com>:
> 
> On Fri, 2008-04-04 at 12:05 -0600, Alex Chiang wrote:
> > Hi Badari,
> > 
> > * Badari Pulavarty <pbadari@us.ibm.com>:
> > > Hi Andrew & Alex,
> > > 
> > > I get following panic in rpaphp_register_slot() on
> > > 2.6.25-rc8-mm1. Known issue ?
> > 
> > I know about it now... :-/
> > 
> > Any chance you could turn debugging on for both rpaphp and
> > pci_hotplug?
> > 
> 
> I did set "debug" variables in rpaphp_core.c and pci_hotplug_core.c
> to 1. But it didn't give any more information. How do I enable
> the debug ?

If those modules are built into your kernel, then you'll need to
modify the kernel command line to add:

	rpaphp.debug=1 pci_hotplug.debug=1

If you're manually modprobing them:

	$ modprobe pci_hotplug debug=1
	$ modprobe rpaphp debug=1

> I just changed dbg() to printk() in rpaphp_register_slot() to
> print out more information.
> 
> Thanks,
> Badari
> 
> 
> pci_hotplug: PCI Hot Plug PCI Core version: 0.5
> rpaphp: RPA HOT Plug PCI Controller Driver version: 0.1
> rpaphp_register_slot registering slot:path[/pci@800000020000003/pci@2,4] index[22010003], name[U787E.001.AAA3015-P2-C1] pdomain[22010003] type[16]
> Unable to handle kernel paging request for data at address 0x00000070

Hrm, this is a little more information, but still not quite
enough. I'm going to take a stab in the dark and say I'm probably
doing something wrong on this line, maybe dereferencing a pointer
incorrectly:

        retval = pci_hp_register(php_slot, slot->bus,
				 PCI_SLOT(PCI_DN(slot->dn->child)->devfn));

But what the real answer is, I don't know, since I don't know
anything about POWER.

Linas -- can you help me out and tell me if I'm doing anything
obviously stupid?

Thanks.

/ac

> Faulting instruction address: 0xc00000000031e4ac
> Oops: Kernel access of bad area, sig: 11 [#1]
> SMP NR_CPUS=32 NUMA pSeries
> Modules linked in:
> NIP: c00000000031e4ac LR: c00000000031e434 CTR: 800000000013f270
> REGS: c0000000700dba30 TRAP: 0300   Not tainted  (2.6.25-rc8-mm1)
> MSR: 8000000000009032 <EE,ME,IR,DR>  CR: 22002022  XER: 00000004
> DAR: 0000000000000070, DSISR: 0000000040000000
> TASK = c0000000700d7990[1] 'swapper' THREAD: c0000000700d8000 CPU: 0
> GPR00: c0000000006c6f10 c0000000700dbcb0 c0000000007691c0 c000000070372440 
> GPR04: c000000070217400 0000000000000001 0000000000000000 0000000000000001 
> GPR08: c0000000007917cc 0000000000000000 00000000000050b3 c0000000007917c8 
> GPR12: 0000000000004000 c000000000690400 0000000000000000 0000000000000000 
> GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
> GPR20: 4000000001c00000 0000000000000000 0000000002247c38 0000000000000000 
> GPR24: 0000000002247ea8 c000000071fff1b8 0000000000000000 c0000000023e8f48 
> GPR28: c000000070372440 c00000006e036780 c0000000006f77f8 c0000000006c6f10 
> NIP [c00000000031e4ac] .rpaphp_register_slot+0xcc/0x158
> LR [c00000000031e434] .rpaphp_register_slot+0x54/0x158
> Call Trace:
> [c0000000700dbcb0] [c00000000031e434] .rpaphp_register_slot+0x54/0x158 (unreliable)
> [c0000000700dbd40] [c00000000031dd60] .rpaphp_add_slot+0x1a4/0x260
> [c0000000700dbe20] [c000000000636864] .rpaphp_init+0x34/0x68
> [c0000000700dbea0] [c0000000006103ec] .kernel_init+0x1f8/0x38c
> [c0000000700dbf90] [c000000000023f80] .kernel_thread+0x4c/0x68
> Instruction dump:
> 48000020 e8bd0020 e89e8010 e87e8048 4bd38c15 60000000 3860fff5 48000080 
> e93d0028 e89d0030 7f83e378 e9290038 <e9290070> 80a90004 78a5eee2 4bffee89 
> ---[ end trace 561bb236c800851f ]---
> 
> 
>