Re: BUG: using smp_processor_id() in preemptible [00000000] code: pm-suspend/17334

[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.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.