baruch at tkos
Aug 11, 2013, 8:03 PM
Post #4 of 4
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Re: [Linux-Xtensa] Re: [PATCH] time: sched_clock: fix integer overflow
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Hi Thomas, John,
On Mon, Jul 29, 2013 at 08:59:39AM +0300, Baruch Siach wrote:
> On Wed, Jul 17, 2013 at 12:46:53PM +0300, Baruch Siach wrote:
> > The expression '(1 << 32)' happens to evaluate as 0 on ARM, but it evaluates as
> > 1 on xtensa and x86_64. This zeros sched_clock_mask, and breaks sched_clock().
> > Set the type of 1 to 'unsigned long long' to get the value we need.
>
> Ping? -rc3 is out, and this bug (which currently breaks xtensa) is not fixed
> yet. Please consider applying.
Sorry to bother again, but -rc5 is here and xtensa sched_clock is still
broken.
baruch
> > Reported-by: Max Filippov <jcmvbkbc [at] gmail>
> > Tested-by: Max Filippov <jcmvbkbc [at] gmail>
> > Acked-by: Russell King <rmk+kernel [at] arm>
> > Signed-off-by: Baruch Siach <baruch [at] tkos>
> > ---
> > kernel/time/sched_clock.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/kernel/time/sched_clock.c b/kernel/time/sched_clock.c
> > index a326f27..0b479a6 100644
> > --- a/kernel/time/sched_clock.c
> > +++ b/kernel/time/sched_clock.c
> > @@ -121,7 +121,7 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
> > BUG_ON(bits > 32);
> > WARN_ON(!irqs_disabled());
> > read_sched_clock = read;
> > - sched_clock_mask = (1 << bits) - 1;
> > + sched_clock_mask = (1ULL << bits) - 1;
> > cd.rate = rate;
> >
> > /* calculate the mult/shift to convert counter ticks to ns. */
> > --
--
http://baruch.siach.name/blog/ ~. .~ Tk Open Systems
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