On 03/11/2012 10:43 PM, Fernando Luis V?zquez Cao wrote: > > To tackle this issue we can either stop the hardlockup detector > or disable the LAPIC (the NMIs needed by x86's hardlockup detector > are generated using performance counters in the LAPIC), leaving > the I/O APICs untouched. The second is simpler and I think it > is the approach Don took to fix this issue in RHEL kernels. > > Unfortunately, this is not enough, we are still exposed to external > NMIs not routed through the LAPIC. In other words, we have to make > sure that we always have and IDT that is able to handle NMIs without > seemingly random reboots and lockups. To achieve this goal we need > to fix machine_kexec() and the early IDT handlers. The current patch > set takes care of the latter. > The only source of NMIs other than the LAPIC should be the system error which can be disabled through the RTC port, so I think your second paragraph here is way more mechanism than you need for very little gain. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
