On Mon, Nov 14, 2016 at 02:42:49PM -0500, Chris Metcalf wrote:
> This bugfix was originally made in commit 35a4933a8959 ("time:
> Avoid signed overflow in timekeeping_get_ns()"). When the code was
> refactored in commit 6bd58f09e1d8 ("time: Add cycles to nanoseconds
> translation") the signed overflow fix was lost. Re-introduce it.
>
> Signed-off-by: Chris Metcalf <[email protected]>Reviewed-by: David Gibson <[email protected]> > --- > I happened to be looking for an unrelated fix, found this code, > realized the tip code didn't match the fixed code, and > backtracked to where it had gone away. > > kernel/time/timekeeping.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c > index 37dec7e3db43..57926bc7b7f3 100644 > --- a/kernel/time/timekeeping.c > +++ b/kernel/time/timekeeping.c > @@ -304,8 +304,7 @@ static inline s64 timekeeping_delta_to_ns(struct > tk_read_base *tkr, > { > s64 nsec; > > - nsec = delta * tkr->mult + tkr->xtime_nsec; > - nsec >>= tkr->shift; > + nsec = (delta * tkr->mult + tkr->xtime_nsec) >> tkr->shift; > > /* If arch requires, add in get_arch_timeoffset() */ > return nsec + arch_gettimeoffset(); -- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson
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