On Sun, Feb 05, 2023 at 06:17:01PM -0500, Peter Xu wrote: > I noticed a few collision usage on VM_FAULT_* definition in the page fault > path on arm/arm64/s390 where the VM_FAULT_* can overlap with the generic > definition of vm_fault_reason. > > The major overlapped part being VM_FAULT_HINDEX_MASK which is used only by > the hugetlb hwpoisoning. > > I'm not sure whether any of them can have a real impact, but that does not > look like to be expected. I didn't copy stable, if anyone thinks it should > please shoot. Nor did I test them in any form - I just changed the > allocations from top bits and added a comment for each of them. This seems like a bad way to do it. Why not just put these VM_FAULT_* definitions in linux/mm_types.h? Then we'll see them when adding new VM_FAULT codes. Sure, they won't be used by every architecture, but so what?