* Ingo Molnar <mingo@xxxxxxx> wrote: > * Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote: > > > David put into its tree fix for that a few hours ago > > > > commit fa9a86ddc8ecd2830a5e773facc250f110300ae7 > > > > (netfilter: iptables: lock free counters) forgot to disable BH > > in arpt_do_table(), ipt_do_table() and ip6t_do_table() > > > > Use rcu_read_lock_bh() instead of rcu_read_lock() cures the problem. > > ok, got your fix (attached below), thanks Eric for the pointer. > > But i think my fix might be slightly better, because it does not > manipulate the preempt counter and leaves preemption enabled. > > There's no BH context worries since this code did not seem to have > BH protection before either. (it used a plain read_lock(), not > read_lock_bh(), AFAICS) > > I dont see any preemption worries either. I must be missing > something :) as per the other mail - what i missed was that the old code _did_ use read_lock_bh(), which did not get carried over into the rcu_read_lock(). So this fix affects basically all things netfilter, not just rcu-preempt - a plain rcu_read_lock() doesnt protect against BH context interaction. Ingo -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
