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

[Herbert Xu]

Eric Biggers <ebiggers@xxxxxxxxxx> wrote:
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
> 
> 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,
-- 
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
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