On 07/01/2016 09:07 AM, Linus Torvalds wrote: > But I also started worrying about us just losing sight of the dirty > bit in particular. It's not enough that we ignore the dirty bit - we'd > still want to make sure that the underlying backing page gets marked > dirty, even if the CPU is buggy and ends doing it "delayed" after > we've already unmapped the page. > > So I get this feeling that we may need a fair chunk of your > patch-series anyway.
As I understand it, the erratum only affects a thread which is about to page fault. The write associated with the dirty bit being set never actually gets executed. So, the bit really *is* stray and isn't something we need to preserve. Otherwise, we'd be really screwed because we couldn't ever simply clear it.
