On Sat, 5 Jan 2019, Linus Torvalds wrote: > > There are possibilities [1] how mincore() could be used as a converyor of > > a sidechannel information about pagecache metadata. > > Can we please just limit it to vma's that are either anonymous, or map > a file that the user actually owns? > > Then the capability check could be for "override the file owner check" > instead, which makes tons of sense. Makes sense. I am still not completely sure what to return in such cases though; we can either blatantly lie and always pretend that the pages are resident (to avoid calling process entering some prefaulting mode), or return -ENOMEM for mappings of files that don't belong to the user (in case it's not CAP_SYS_ADMIN one). -- Jiri Kosina SUSE Labs
