Messages in this thread | | | From | Eric Dumazet <> | Date | Thu, 7 Nov 2019 08:35:30 -0800 | Subject | Re: [tip: timers/core] hrtimer: Annotate lockless access to timer->state |
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On Thu, Nov 7, 2019 at 8:11 AM Paul E. McKenney <paulmck@kernel.org> wrote: > > OK, so this is due to timer_pending() lockless access to ->entry.pprev > to determine whether or not the timer is on the list. New one on me! > > Given that use case, I don't have an objection to your patch to list.h. > > Except... > > Would it make sense to add a READ_ONCE() to hlist_unhashed() > and to then make timer_pending() invoke hlist_unhashed()? That > would better confine the needed uses of READ_ONCE().
Sounds good to me, I had the same idea but was too lazy to look at the history of timer_pending() to check if the pprev pointer check was really the same underlying idea.
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