Re: [PATCH REPOST] random: Add a spinlock_t to struct batched_entropy

From: Theodore Ts'o
Date: Sun Apr 28 2019 - 14:29:59 EST

On Fri, Apr 26, 2019 at 12:34:38PM +0200, Sebastian Andrzej Siewior wrote:
> The per-CPU variable batched_entropy_uXX is protected by get_cpu_var().
> This is just a preempt_disable() which protects against concurrent
> access from process context on the local CPU. It does not protect
> against users on the same CPU from another context. It is possible that
> a preemptible context reads slot 0 and then an interrupt occurs and the
> same value is read again from hard or soft IRQ context.

This patch is already on the random.git tree. (It wasn't in
linux-next because I had forgotten that linux-next pulls from the dev
branch, as opposed to the master branch.)


- Ted