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

Eric Biggers ebiggers@kernel.org wrote:

From: Eric Biggers ebiggers@google.com

When a CPU selects which CRNG to use, it accesses crng_node_pool without a memory barrier. That's wrong, because crng_node_pool can be set by another CPU concurrently. Without a memory barrier, the crng_state that is used might not appear to be fully initialized.

The only architecture that requires a barrier for data dependency is Alpha. The correct primitive to ensure that barrier is present is smp_barrier_depends, or you could just use READ_ONCE.

Cheers,