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Message-ID: <c4e36d110806040257y698dbde4w4e717522478b74b8@mail.gmail.com>
Date: Wed, 4 Jun 2008 11:57:09 +0200
From: "Zdenek Kabelac" <zdenek.kabelac@gmail.com>
To: "Avi Kivity" <avi@qumranet.com>
Subject: Re: BUG: using smp_processor_id() in preemptible [00000000] code: pm-suspend/17334
Cc: "Jiri Kosina" <jkosina@suse.cz>, linux-kernel@vger.kernel.org,
       kvm@vger.kernel.org
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2008/6/4 Avi Kivity <avi@qumranet.com>:
> Jiri Kosina wrote:
>>
>> [ re-introduced LKML to CC, and also added KVM CCs]
>>
>> On Tue, 3 Jun 2008, Zdenek Kabelac wrote:
>>
>>
>>>
>>> 2008/6/3 Jiri Kosina <jkosina@suse.cz>:
>>>
>>>>
>>>> On Tue, 3 Jun 2008, Zdenek Kabelac wrote:
>>>>
>>>>
>>>>>
>>>>> Another backtrace from suspend code path:
>>>>> (T61, 2GB, C2D, no SD card)
>>>>> kernel from git 20080603, commit
>>>>> 1beee8dc8cf58e3f605bd7b34d7a39939be7d8d2
>>>>> ----
>>>>> agpgart-intel 0000:00:00.0: LATE suspend
>>>>> platform bay.0: LATE suspend
>>>>> platform dock.0: LATE suspend
>>>>> Extended CMOS year: 2000
>>>>>  hwsleep-0324 [00] enter_sleep_state     : Entering sleep state [S3]
>>>>> Back to C!
>>>>> BUG: using smp_processor_id() in preemptible [00000000] code:
>>>>> pm-suspend/17334
>>>>> caller is do_machine_check+0xa9/0x500
>>>>> Pid: 17334, comm: pm-suspend Not tainted 2.6.26-rc4 #31
>>>>> Call Trace:
>>>>>  [<ffffffff8118347c>] debug_smp_processor_id+0xcc/0xd0
>>>>>  [<ffffffff810184d9>] do_machine_check+0xa9/0x500
>>>>>  [<ffffffff81010e7b>] ? init_8259A+0x1b/0x120
>>>>>  [<ffffffff810189d6>] mce_init+0x56/0xf0
>>>>>  [<ffffffff81018a7b>] mce_resume+0xb/0x10
>>>>>  [<ffffffff81204fd0>] __sysdev_resume+0x20/0x60
>>>>>  [<ffffffff81205068>] sysdev_resume+0x58/0x90
>>>>>  [<ffffffff8120aac9>] device_power_up+0x9/0x10
>>>>>  [<ffffffff8106f4f7>] suspend_devices_and_enter+0x147/0x1a0
>>>>>  [<ffffffff8106f6c6>] enter_state+0x146/0x1d0
>>>>>  [<ffffffff8106f80a>] state_store+0xba/0x100
>>>>>  [<ffffffff81177ae7>] kobj_attr_store+0x17/0x20
>>>>>  [<ffffffff81110fea>] sysfs_write_file+0xca/0x140
>>>>>  [<ffffffff810ba00b>] vfs_write+0xcb/0x190
>>>>>  [<ffffffff810ba1c0>] sys_write+0x50/0x90
>>>>>  [<ffffffff8100c4fb>] system_call_after_swapgs+0x7b/0x80
>>>>>
>>>>
>>>> This looks very much like the oops you reported here:
>>>> http://lkml.org/lkml/2008/4/7/130
>>>>
>>>> Is this also a virtual machine run under KVM, as it has been in the
>>>> aforementioned thread?
>>>>
>>>
>>> Ahh yes - you are right , I've completely forget about that old post -
>>> I've thought  that my post are usually getting fixed sooner :)
>>> So yes - this is actually the same bug which is still not fixed within
>>> the latest kernel - the machine is running qemu guest (which seems to
>>> me now somehow also slower)
>>>
>>
>> OK, so it looks like KVM could be wrongly enabling IRQs/preemption on the
>> resume path. The original bug-report is on http://lkml.org/lkml/2008/4/7/130
>>
>>
>
> Wait, is this in a virtual machine, or on a host that's also running a
> virtual machine (or has the kvm modules loaded)?
>
> I looked at the kvm host resume path, and it doesn't touch interrupts.

Oops is from my real-hardware T61 (host) running the kvm-qemu (guest)
and was noticed after suspend.
But everything seemed to work just fine - host&guest continued to
operate normally after resume.

Zdenek
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