Re: ntp: BUG: spinlock lockup on CPU#1

From: Sasha Levin
Date: Thu Mar 15 2012 - 10:52:25 EST


On Thu, Mar 15, 2012 at 4:04 PM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> On Thu, 15 Mar 2012, Sasha Levin wrote:
>
>> On Thu, Mar 15, 2012 at 3:23 PM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote:
>> > Hi all,
>> >
>> > I was doing some more fuzzing with trinity in a KVM tools guest, using
>> > today's linux-next, when I've experienced a complete system lockup
>> > (just in the guest ofcourse). After a bit I got the spew at the bottom
>> > of this mail.
>> >
>> > From what I can tell from the logs, there were several threads waiting
>> > on syscall results, and I suspect that the adjtimex() call on CPU3 is
>> > somehow responsible for this lockup.
>>
>> Oh, and I'm not sure if it's related or not, but I've started seeing
>> the following spew every time I start fuzzing:
>>
>> [   47.105987] ------------[ cut here ]------------
>> [   47.106021] WARNING: at kernel/time/clockevents.c:209
>
> It's unrelated, but I'm mighty curious how you manage that.

>From what I gather from the logs it's the result of adjtimex() being
called while a different CPU is in the middle of a syscall. It happens
quite often really, so I can get that warning to jump out pretty
easily.
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