Re: [PATCH 02/10] random: use lockless techniques when mixingentropy pools

[Theodore Ts'o]

On Thu, Jul 05, 2012 at 02:10:12PM -0500, Matt Mackall wrote:
> 
> I don't think this will work correctly. It's important that simultaneous
> _readers_ of the state get different results. Otherwise, you can get
> things like duplicate UUIDs generated on different cores, something
> that's been observed in the field(!). I thought I added a comment to
> that effect some years back, but I guess not.

That's easy to fix; we just need to take a spinlock on the extract
side.  The main issue is that Thomas very much doesn't want us to take
a spinlock in the interrupt handler codepath.  But if we take a
spinlock while extracting, that should take care of this concern.

	       		   	       	    - Ted
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/