On 03/15/2018 02:46 AM, Thomas Gleixner wrote: >> + if (!pkey || !mm_pkey_is_allocated(mm, pkey)) > Why this extra check? mm_pkey_is_allocated(mm, 0) should not return true > ever. If it does, then this wants to be fixed. I was thinking that we _do_ actually want it to seem allocated. It just get "allocated" implicitly when an mm is created. I think that will simplify the code if we avoid treating it specially in as many places as possible.