On Tue, 29 Apr 2014, Jiri Bohac wrote: > Thomas, does this make sense now, with the new description?
Yep, except > On Fri, Apr 18, 2014 at 05:23:11PM +0200, Jiri Bohac wrote: > > On architectures with sizeof(int) < sizeof (long), the > > computation of mask inside apply_slack() can be undefined if the > > computed bit is > 32. > > > > E.g. with: expires = 0xffffe6f5 and slack = 25, we get: > > > > expires_limit = 0x20000000e > > bit = 33 > > mask = (1 << 33) - 1 /* undefined */ > > > > On x86, mask becomes 1 and and the slack is not applied properly. > > On s390, mask is -1, expires is set to 0 and the timer fires immediately. > > > > Signed-off-by: Jiri Bohac <[email protected]> > > Suggested-by: Deborah Townsend <[email protected]> > > > > diff --git a/kernel/timer.c b/kernel/timer.c > > index 87bd529..4c36c91 100644 > > --- a/kernel/timer.c > > +++ b/kernel/timer.c > > @@ -838,7 +838,7 @@ unsigned long apply_slack(struct timer_list *timer, > > unsigned long expires) > > > > bit = find_last_bit(&mask, BITS_PER_LONG); > > > > - mask = (1 << bit) - 1; > > + mask = (1LL << bit) - 1; This should be 1UL, shouldn't it? > > expires_limit = expires_limit & ~(mask); > > > > Thanks, > > -- > Jiri Bohac <[email protected]> > SUSE Labs, SUSE CZ > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
