On Wed, Mar 17, 2021 at 04:44:25PM -0400, Brian Geffon wrote: > Hi Peter, Hi, Brian, > Thank you as always for taking a look. This change relies on the > existing check in vma_to_resize on line 686: > https://elixir.bootlin.com/linux/v5.12-rc3/source/mm/mremap.c#L686 > which returns -EFAULT when the vma is VM_DONTEXPAND or VM_PFNMAP. Do you mean line 676? https://elixir.bootlin.com/linux/v5.12-rc3/source/mm/mremap.c#L676 I'm not sure whether it'll work for MREMAP_DONTUNMAP, since IIUC MREMAP_DONTUNMAP only works for the remap case with no size change, however in that case in vma_to_resize() we'll bail out even earlier than line 676 when checking against the size: https://elixir.bootlin.com/linux/v5.12-rc3/source/mm/mremap.c#L667 So IIUC we'll still need the change as Hugh suggested previously. Thanks, -- Peter Xu
