On Mon, Jun 03, 2024 at 09:37:46AM -0700, Dave Hansen wrote: > Yeah, we'd need some equivalent of a PTE marker, but for the page cache. > Presumably some xa_value() that means a reader has to go do a > luf_flush() before going any farther. I can allocate one for that. We've got something like 1000 currently unused values which can't be mistaken for anything else. > That would actually have a chance at fixing two issues: One where a new > page cache insertion is attempted. The other where someone goes to look > in the page cache and takes some action _because_ it is empty (I think > NFS is doing some of this for file locks). > > LUF is also pretty fundamentally built on the idea that files can't > change without LUF being aware. That model seems to work decently for > normal old filesystems on normal old local block devices. I'm worried > about NFS, and I don't know how seriously folks take FUSE, but it > obviously can't work well for FUSE. I'm more concerned with: - page goes back to buddy - page is allocated to slab - application reads through stale TLB entry and sees kernel memory Or did that scenario get resolved?
