Re: BUG: using smp_processor_id() in preemptible [00000000] code:icedove-bin/5449

[Piotr Hosowicz]

On 25.05.2010 12:00, Peter Zijlstra wrote:
> On Tue, 2010-05-25 at 11:57 +0200, Piotr Hosowicz wrote:
> > On 25.05.2010 11:43, Ingo Molnar wrote:
> >
> > > This doesnt fix the whole issue. cpu_clock() is local, while the measurements
> > > done in the blk code are global ...
> > >
> > > While the warning is fixed this way, the far more serious issue is still
> > > there: time can go backwards if two points of time measurement are on
> > > different CPUs and can mess up the statistics with negative values, etc...
> >
> > How serious is this? Can it damage my data? I ask because the machine is
> > my private computer, not any test machine.
>
> I'm not sure, since I didn't really look what they use the timestamps
> for, but a guess would say your data is safe, it might schedule the io
> funny, but it should not compromise integrity. At best its used purely
> for statistics and not even behaviour is affected.

Thanks.

Cheers,

Piotr Hosowicz

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