Re: 2.6.31.4: WARNING: at arch/x86/kernel/hpet.c:390 hpet_next_event+0x70/0x80() [occurs when ACPI_PROCESSOR=y]

[Justin Piszcz <jpiszcz@lucidpixels.com>]

On Thu, 12 Nov 2009, john stultz wrote:

> Forgot to CC lkml, re-adding.
>
> On Thu, 2009-11-12 at 18:25 -0500, Justin Piszcz wrote:
>> On Thu, 12 Nov 2009, john stultz wrote:
>>> On Thu, Nov 12, 2009 at 8:33 AM, Justin Piszcz <jpiszcz@lucidpixels.com> wrote:
>>>> On Thu, 12 Nov 2009, Justin Piszcz wrote:
>>>>> On Wed, 11 Nov 2009, Justin Piszcz wrote:
>>>>> Again, the problem:
>>>>> [    3.318770] cpuidle: using governor ladder
>>>>> [    3.321556] ------------[ cut here ]------------
>>>>> [    3.321560] WARNING: at arch/x86/kernel/hpet.c:390
>>>>> hpet_next_event+0x70/0x80()
>>>>> [    3.321561] Hardware name:
>>>>> [    3.321562] Modules linked in:
>>>>> [    3.321564] Pid: 0, comm: swapper Not tainted 2.6.31.5 #17
>>>>> [    3.321565] Call Trace:
>>>>> [    3.321567]  [<ffffffff81042f00>] ? hpet_next_event+0x70/0x80
>>>>> [    3.321568]  [<ffffffff81042f00>] ? hpet_next_event+0x70/0x80
>>>>> [    3.321571]  [<ffffffff81056724>] ? warn_slowpath_common+0x74/0xd0
>>>>> [    3.321573]  [<ffffffff81042f00>] ? hpet_next_event+0x70/0x80
>>>>> [    3.321576]  [<ffffffff81077696>] ? tick_dev_program_event+0x36/0xb0
>>>>> [    3.321578]  [<ffffffff81077079>] ?
>>>>> tick_broadcast_oneshot_control+0x119/0x120
>>>>> [    3.321579]  [<ffffffff8107683d>] ? tick_notify+0x22d/0x420
>>>>> [    3.321581]  [<ffffffff8106fe37>] ? notifier_call_chain+0x37/0x70
>>>>> [    3.321583]  [<ffffffff8107612b>] ? clockevents_notify+0x2b/0x90
>>>>> [    3.321586]  [<ffffffff81244848>] ? acpi_idle_enter_bm+0x15f/0x2d3
>>>>> [    3.321587]  [<ffffffff812446de>] ? acpi_idle_enter_c1+0xf1/0xfc
>>>>> [    3.321590]  [<ffffffff812e6d7a>] ? cpuidle_idle_call+0xba/0x120
>>>>> [    3.321593]  [<ffffffff8102b832>] ? cpu_idle+0x62/0xc0
>>>>> [    3.321596] ---[ end trace cac202f11005305c ]---
>>>>> [    3.553852] cpuidle: using governor menu
>>>>
>>>> Other user with this problem:
>>>> http://lkml.org/lkml/2009/10/2/330 - Nobody responded to his report.
>>>>
>>>> This has been also been reported on other forums with no fix / conclusion on
>>>> any type of fix or work-around.
>>>
>>> Looks like your hpet is busted, or maybe something is resetting the
>>> hpet at exactly the wrong time.
>>>
>>> What does booting with the attached patch do?
>>
>> Unfortunately I cannot login fast enough to get a full dmesg:
>
> So if you comment out the printk I added, does it boot?
I can login ok, its just a little slower with the message printing so quickly.

>
>> It continually scrolls with this:
>>
>> [   11.463500] hpet_next_event: hpet_writel failed: 0x9c90955 != 0xa0e8b7b
>> [   11.463972] hpet_next_event: hpet_writel failed: 0xa0e8b7b != 0x9cb9398
>> [   11.475121] hpet_next_event: hpet_writel failed: 0x9cb9398 != 0xa0e8b71
>> [   11.475144] hpet_next_event: hpet_writel failed: 0xa0e8b71 != 0x9ce0459
>> [   11.486274] hpet_next_event: hpet_writel failed: 0x9ce0459 != 0xa0e8b61
>> [   11.486343] hpet_next_event: hpet_writel failed: 0xa0e8b61 != 0x9d076c0
>> [   11.497492] hpet_next_event: hpet_writel failed: 0x9d076c0 != 0xa0e8b4c
>> [   11.497962] hpet_next_event: hpet_writel failed: 0xa0e8b4c != 0x9d30119
>> [   11.509111] hpet_next_event: hpet_writel failed: 0x9d30119 != 0xa0e8b3c
>> [   11.509134] hpet_next_event: hpet_writel failed: 0xa0e8b3c != 0x9d571a9
>> [   11.520275] hpet_next_event: hpet_writel failed: 0x9d571a9 != 0xa0e8b2f
>> [   11.520293] hpet_next_event: hpet_writel failed: 0xa0e8b2f != 0x9d7e24d
>> [   11.531443] hpet_next_event: hpet_writel failed: 0x9d7e24d != 0xa0e8b1d
>> [   11.531947] hpet_next_event: hpet_writel failed: 0xa0e8b1d != 0x9da6e46
>> [   11.543095] hpet_next_event: hpet_writel failed: 0x9da6e46 != 0xa0e8b0c
>
> Huh. That's sort of crazy. It almost seems as though you have two offset
> HPET timers at one timer location that are switching back and forth.
> Looks like either very busted hardware, or something new the kernel
> doesn't expect.
Busted HW? Brand new motherboard.  My guess its something the kernel does not
expect.  When I bought a new Intel motherboard a few years ago there were 
issues when you ran it with 8GB of RAM-- the memory allocations were 
not correct and it acted like a 286, Intel did not fix the BIOS until
a few revisions later.

>
>
>> When I do not load processor.ko though, the error does not occur?
>
> Hrm. No clue right off.
>
> -john

The culprit here is processor.ko.

I am running 2.6.31.5 with your patch and processor.ko removed from the kernel.
No problems.

When processor.ko is loaded, then the timers go crazy.  ACPI/processor module 
bug?

Justin.