On Sat, Dec 08, 2018 at 12:47:30PM -0500, Jerome Glisse wrote: > Most of the user of GUP are well behave (everything under driver/gpu and > so is mellanox driver and many other) ie they abide by mmu notifier > invalidation call backs. They are a handfull of device driver that thought > they could just do GUP and ignore the mmu notifier part and those are the > one being problematic. So to me it feels like bystander are be shot for no > good reasons. get_user_pages is used by every single direct I/O, and while the race windows in that case are small they very much exists.