Subject: Re: RCU lockup issues when CONFIG_SOFTLOCKUP_DETECTOR=n - any one else seeing this?

From: "Paul E. McKenney" <[email-masked]>
Date: Sat, 19 Aug 2017 22:04:52 -0700

On Sun, Aug 20, 2017 at 02:45:53PM +1000, Nicholas Piggin wrote:
> On Wed, 16 Aug 2017 09:27:31 -0700
> "Paul E. McKenney" <[email-masked]> wrote:
> > On Wed, Aug 16, 2017 at 05:56:17AM -0700, Paul E. McKenney wrote:
> > 
> > Thomas, John, am I misinterpreting the timer trace event messages?
> 
> So I did some digging, and what you find is that rcu_sched seems to do a
> simple scheudle_timeout(1) and just goes out to lunch for many seconds.
> The process_timeout timer never fires (when it finally does wake after
> one of these events, it usually removes the timer with del_timer_sync).
> 
> So this patch seems to fix it. Testing, comments welcome.

Fired up some tests, which should complete in about 12 hours.

Here is hoping!  ;-)

							Thanx, Paul