Re: [PATCH v3 1/5] genirq: Synchronize in-flight handlers during NMI teardown

[Doug Anderson]

Hi,

On Wed, Sep 30, 2026 at 2:46 PM Thomas Gleixner <tglx@xxxxxxxxxx> wrote:
>
> On Mon, Sep 28 2026 at 09:14, Doug Anderson wrote:
> > On Fri, Sep 4, 2026 at 8:26 AM Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> >> On Fri, Sep 4, 2026 at 8:11 AM Thomas Gleixner <tglx@xxxxxxxxxx> wrote:
> >> > Of course this is a regular global interrupt otherwise it couldn't be
> >> > requested normally. So this sets IRQF_PERCPU (it has to otherwise
> >> > request_nmi() would fail), but that looks like a hack to me.
> >>
> >> At least on GIC, promoting a regular global interrupt to NMI (or
> >> pseudo-NMI) level is possible, and Mayank's use case here seems
> >> legitimate. Any suggestions you have for making this look less like a
> >> hack are appreciated! :-)
> >
> > Throwing an extra plea out here to see if we can make forward
> > progress. IMO being able to make watchdog driver "bark" interrupts run
> > at NMI (or pseudo-NMI) level is an important thing to do for
> > debuggability of the kernel. It sounds as if there are no general
> > objections to the idea. I guess the next step is to make this look
> > less hacky. Is that something we could send patches for? Any hints for
> > what you'd like this to look like would be greatly appreciated.
>
> I think the objections have been layed out in course of the discussion, no?

I guess I'm still unclear on one key question: if we post up clean
patches that allow promoting global interrupts to NMI (or pseudo-NMI)
level, would you be willing to review and eventually land? I got a bit
of a vibe that you just didn't like the idea in general, but maybe I
misunderstood. I just want to make sure Mayank doesn't spend a bunch
of time trying to solve this problem if it has zero chance of actually
landing.


> > I'll also be in Prague next week for both Plumbers and ELCE, so I'd be
> > happy to discuss this in person if that helps.
>
> I'm going to be there, but I don't know about Marc.

Great, I'll make sure to look for you.

-Doug