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SubjectRe: [PATCH RFC] doc: rcu: remove obsolete (non-)requirement about disabling preemption
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@linux.ibm.com> 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

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