Re: [PATCH RFC tip/core/rcu 14/15] netfilter: Remove now-redundant smp_read_barrier_depends()

[Peter Zijlstra]

On Mon, Oct 09, 2017 at 05:22:48PM -0700, Paul E. McKenney wrote:
> READ_ONCE() now implies smp_read_barrier_depends(), which means that
> the instances in arpt_do_table(), ipt_do_table(), and ip6t_do_table()
> are now redundant.  This commit removes them and adjusts the comments.

Similar to the previous patch, the lack of READ_ONCE() in the original
code is a pre-existing bug. It would allow the compiler to tear the load
and observe a composite of two difference pointer values, or reload the
private pointer and result in table_base and jumpstacl being part of
different objects.

It would be good to point out this actually fixes a bug in the code.