Messages in this thread | | | Date | Mon, 29 Jul 2013 08:59:39 +0300 | From | Baruch Siach <> | Subject | Re: [PATCH] time: sched_clock: fix integer overflow |
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Hi Thomas, John,
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.
baruch
> Reported-by: Max Filippov <jcmvbkbc@gmail.com> > Tested-by: Max Filippov <jcmvbkbc@gmail.com> > Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> > Signed-off-by: Baruch Siach <baruch@tkos.co.il> > --- > 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. */ > --
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