On Tue, 3 Oct 2017, Michael Ellerman wrote: > Thomas Gleixner <t...@linutronix.de> writes: > >> The first call is new because previously watchdog_nmi_reconfigure() > >> wasn't called from softlockup_reconfigure_threads(). > > > > Hmm, don't you have the same problem with CPU hotplug or do you just get > > lucky because the hotplug callback in your code is ordered vs. the > > softlockup thread hotplug callback in a way that this does not hit? > > I don't see it with CPU hotplug. > > AFAICS that's because softlockup_reconfigure_threads() isn't called for > CPU hotplug. Unless there's a path I'm missing?
As I said in the other reply, I assumed that its called via watchdog_nmi_enable(cpu), but that's a weak function which is not implemented on power. So no issue. > >> I'm not sure what the easiest fix is. One option would be to just drop > >> the WARN_ON, it's just there for paranoia AFAICS. > > > > The straight forward way is to make use of the new probe function. Patch > > below. > > Hmm, I tried that patch, it makes the warning go away. But then I > triggered a deliberate hard lockup and got nothing. > > Then I went back to the existing code (in linux-next), and I still get > no warning from a deliberate hard lockup. > > So seems there may be some more gremlins. Will test more in the morning. Hrm. That's weird. I'll have a look and send a proper patch series on top of next. Thanks, tglx