On Mon, Jan 23, 2023 at 11:05 PM Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> wrote: > > untagged_addr() is a helper used by the core-mm to strip tag bits and > get the address to the canonical shape based on rules of the current > thread. It only handles userspace addresses. > > The untagging mask is stored in per-CPU variable and set on context > switching to the task. > > The tags must not be included into check whether it's okay to access the > userspace address. Strip tags in access_ok(). > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Tested-by: Alexander Potapenko <glider@xxxxxxxxxx>
