On Wed, Nov 23, 2022 at 11:06:55AM +0100, Daniel Vetter wrote: > > Maybe a GFP flag to set the page reference count to zero or something > > like this? > > Hm yeah that might work. I'm not sure what it will all break though? > And we'd need to make sure that underflowing the page refcount dies in > a backtrace. Mucking with the refcount like this to protect against crazy out of tree drives seems horrible.. The WARN_ON(pag_count(p) != 1) seems like a reasonable thing to do though, though you must combine this with the special PTE flag.. Jason