Messages in this thread | | | Date | Tue, 27 Oct 2015 17:06:27 +0800 | From | "'Baoquan He'" <> | Subject | Re: [V4 PATCH 4/4] x86/apic: Introduce noextnmi boot option |
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On 10/27/15 at 09:01am, 河合英宏 / KAWAI,HIDEHIRO wrote: > Hi, > > > I just have a look at this thread. I am wondering why we don't use > > existing is_kdump_kernel() directly to disable external NMI if it's > > in kdump kernel. Then no need to introduce another boot option "noextnmi" > > which is used only for kdump kernel. > > As I stated in another mail, there is a case where we don't want to > mask external NMIs in the second kernel. So, we need some > configurable way. Please see the following quotation.
Got it. Thanks for telling.
> > > We souldn't enable this feature silently. Some users wouldn't like > > to enable this feature. For example, a user enables a watchdog timer > > which raises an external NMI when the counter is not reset for a > > specific duration. Then, the second kernel hangs up while saving > > crash dump, and NMI is delivered to the CPU. The kernel gets panic > > due to the NMI, prints some information to the display and serial > > console, and then automatically reboot. In this case, users don't > > want to block external NMIs. > > Regards, > > Hidehiro Kawai > Hitachi, Ltd. Research & Development Group > >
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