Re: [PATCH] random: use correct memory barriers for crng_node_pool

On Thu, Sep 17, 2020 at 09:58:02AM -0700, Eric Biggers wrote:

smp_load_acquire() is obviously correct, whereas READ_ONCE() is an optimization that is difficult to tell whether it's correct or not. For trivial data structures it's "easy" to tell. But whenever there is a->b where b is an internal implementation detail of another kernel subsystem, the use of which could involve accesses to global or static data (for example, spin_lock() accessing lockdep stuff), a control dependency can slip in.

If we're going to follow this line of reasoning, surely you should be converting the RCU derference first and foremost, no?

Cheers,