Re: [PATCH RFC] doc: rcu: remove obsolete (non-)requirement about disabling preemption

[Joel Fernandes]

On Thu, Oct 18, 2018 at 09:12:45PM -0400, Steven Rostedt wrote:
> On Thu, 18 Oct 2018 17:19:32 -0700
> "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx> wrote:
> 
> > I figured that whoever calls preempt_enable_no_resched() is taking the
> > responsibility for permitting preemption in the near future, and if they
> > fail to do so, they will get called on it.  Hard to hide from the latency
> > tracer, after all.  ;-)
> 
> Correct, and doing a search of preempt_enable_no_resched() I see
> there's one in the ftrace ring buffer code, that was added a long time
> ago (2008) to fix a recursion bug that no longer exists, and this now
> can leak a preemption point.
> 
> I'll have to go fix that :-(

Cool! Glad you found this issue in the code while we are discussing it ;)

thanks,

- Joel