Insta-reset-bootloop with r328166 and vm.pmap.pcid_enabled=1

[Ian FREISLICH]

On 01/25/18 17:13, Konstantin Belousov wrote:
> On Thu, Jan 25, 2018 at 04:58:04PM -0500, Ian FREISLICH wrote:
>> Hi
>>
>> I cannot for the life of me recall why I had vm.pmap.pcid_enabled=1 set
>> in loader.conf, but I did.  Most likely very historical reasons.
>>
>> r328166 and later reset without dropping into the debugger during boot,
>> no panic message.
> Yes, this is how it is currently behaves.
> PCID can be used to optimize PTI, see https://reviews.freebsd.org/D13985.
> It is used for very differrent algorithm when PTI=1, comparing with PTI=0.

Maybe there should be an "interlock" on these knobs, although judging
from the number of reports I'm the only that shot my foot.

Ian

-- 
Ian Freislich

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