On 2/1/19 10:11 AM, Michal Hocko wrote: > On Fri 01-02-19 10:04:23, Vlastimil Babka wrote: >> The side channel exists anyway as long as process can e.g. check if >> its rss shrinked, and I doubt we are going to remove that possibility. > > Well, but rss update will not tell you that the page has been faulted in > which is the most interesting part. Sure, but the patch doesn't add back that capability neither. It allows to recognize page being reclaimed, and I argue you can infer that from rss change as well. That change is mentioned in the last paragraph in changelog, and I thought "add a hard to evaluate side channel" in your reply referred to that. It doesn't add back the "original" side channel to detect somebody else accessed a page. > You shouldn't be able to sniff on > /proc/$vicimt/smaps as an attacker.
