On Fri, Dec 15, 2017 at 12:32 AM, Nicholas Piggin <npig...@gmail.com> wrote: > On Thu, 14 Dec 2017 23:16:26 +1100 > Balbir Singh <bsinghar...@gmail.com> wrote: > >> On Thu, Dec 14, 2017 at 12:51 PM, Nicholas Piggin <npig...@gmail.com> wrote: > > >> >> I can't call smp_send_nmi_ipi due to the nmi_ipi_busy_count and >> >> I'm worried about calling a stale nmi_ipi_function via the >> >> system_reset_exception path, if we are OK with it, I can revisit >> >> the code path >> > >> > You shouldn't get a stale one, that would also be a bug -- we >> > have to cope with NMIs coming in at any time that are triggered >> > externally (not by smp_send_nmi_ipi), so if you see any bugs >> > there those need to be fixed separately. >> > >> >> Yes, I think it's a bug, nothing clears nmi_ipi_function (from what >> I can see), so when the next NMI comes in and goes into >> pnv_system_reset_exception >> it'll execute the stale handler. > > The CPU won't be in the nmi_ipi_pending_mask though, so it shouldn't > get that far. You could add a bit of paranoia to clear the function > pointer I suppose, but AFAIKS it's not needed. >
Yep your right, but these things are so subtle :) I will as paranoia cleanup nmi_ipi_function, but I'll add that as a TODO Balbir Singh.
