Re: [RFC][PATCH] clocksource: avoid unnecessary overflow in cyclecounter_cyc2ns()

[Mike Galbraith]

On Tue, 2014-03-04 at 14:40 +0800, John Stultz wrote: 
> On Tue, Mar 4, 2014 at 1:38 PM, Mike Galbraith <bitbucket@xxxxxxxxx> wrote:
> > (crap crap crap... M.A.I.N.T.A.I.N.E.R.S _dummy_)
> >
> > clocksource: avoid unnecessary overflow in cyclecounter_cyc2ns()
> >
> > As per 4cecf6d401a "sched, x86: Avoid unnecessary overflow in sched_clock",
> > cycles * mult >> shift is overflow prone. so give it the same treatment.
> >
> > Cc: Salman Qazi <sqazi@xxxxxxxxxx>
> > Cc: John Stultz <john.stultz@xxxxxxxxxx>,
> > Signed-off-by: Mike Galbraith <bitbucket@xxxxxxxxx>
> 
> Thanks for sending this in!  Curious exactly how the issue was being
> triggered?

Dunno that it is.  This is the result of me rummaging around, looking
for any excuse what-so-ever for a small and identical group of weird a$$
boxen running old 2.6.32 kernels (w. 208 day fix!) to manage to hop back
and forth in time by exactly 208 days.  Grep showed me that function, so
I scurried off and swiped the fix.

-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/