Re: [PATCH] Make rcutorture RNG use temporal entropy

Andrew Morton
2007-08-17T18:54:31Z

On Wed, 15 Aug 2007 19:49:04 -0700
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:

> Repost of http://lkml.org/lkml/2007/8/10/472 made available by request.
>
> The locking used by get_random_bytes() can conflict with the
> preempt_disable() and synchronize_sched() form of RCU. This patch changes
> rcutorture's RNG to gather entropy from the new cpu_clock() interface
> (relying on interrupts, preemption, daemons, and rcutorture's reader
> thread's rock-bottom scheduling priority to provide useful entropy),
> and also adds and EXPORT_SYMBOL_GPL() to make that interface available
> to GPLed kernel modules such as rcutorture.
>
> Passes several hours of rcutorture.

Please explain what "conflict with" means so that I can work out if
this is a needed-in-2.6.23 change, thanks.