On Fri, Aug 17, 2007 at 01:00:22PM -0700, Paul E. McKenney wrote: > On Fri, Aug 17, 2007 at 11:53:56AM -0700, Andrew Morton wrote: > > On Wed, 15 Aug 2007 19:49:04 -0700 > > "Paul E. McKenney" <[EMAIL PROTECTED]> 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. > > Not needed in 2.6.23. This change falls into the "preparation for -rt" > category. Also in the "don't unnecessarily eat entropy, leave some for > the people needing crypographically secure randomness" category.
We've had several calls for a more fast and loose version of get_random_bytes. Generalizing one of the cookie generation functions is probably a good way to go. -- Mathematics is the supreme nostalgia of our time. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
