On Mon, Jan 11, 2021 at 11:40 AM Geert Uytterhoeven <geert+rene...@glider.be> wrote: > Due to an integer overflow, RTC synchronization now happens every 2s > instead of the intended 11 minutes. Fix this by forcing 64-bit > arithmetic for the sync period calculation. > > Fixes: c9e6189fb03123a7 ("ntp: Make the RTC synchronization more reliable") > Signed-off-by: Geert Uytterhoeven <geert+rene...@glider.be> > --- > kernel/time/ntp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/time/ntp.c b/kernel/time/ntp.c > index 7404d38315276a96..54d52fab201d283e 100644 > --- a/kernel/time/ntp.c > +++ b/kernel/time/ntp.c > @@ -498,7 +498,7 @@ int second_overflow(time64_t secs) > static void sync_hw_clock(struct work_struct *work); > static DECLARE_WORK(sync_work, sync_hw_clock); > static struct hrtimer sync_hrtimer; > -#define SYNC_PERIOD_NS (11UL * 60 * NSEC_PER_SEC) > +#define SYNC_PERIOD_NS (11ULL * 60 * NSEC_PER_SEC) > > static enum hrtimer_restart sync_timer_callback(struct hrtimer *timer) > {
While the line exp = ktime_add_ns(exp, 2 * NSEC_PER_SEC - offset_nsec); is currently not an issue, it may be wise to change it to exp = ktime_add_ns(exp, 2ULL * NSEC_PER_SEC - offset_nsec); in case someone wants to experiment with values larger then 4s? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds