Stale memory during post fork cow pmap update

[Steven Hartland]

@kib do you think this issue could be the cause of the golang crashes 
during fork that we spoke about a while back
https://github.com/golang/go/issues/15658

If its possible is there anything specific I could do to force a regular 
occurrence in order to confirm or deny it?

On 13/02/2018 21:49, Mike Tancsa wrote:
> On 2/13/2018 8:30 AM, Konstantin Belousov wrote:
>> Apparently Ryzen CPUs are able to demonstrate it quite reliably with the
>> python driver for the samba build.  It was very surprising to me, esp.
>> because I tried to understand the Ryzen bug for the whole last week and
>> thought that it is more likely CPU store/load inconsistency than a software
>> thing.  See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=225584.
> Just tested on an AMD EPYC 7281 (16/32 cores), and it runs into this bug
> every time on the samba build.  Applying the referenced patch fixes the
> problem, at least I was able to test 4 builds in a row without issue.
>
> 	---Mike
>
>