On 08/27, Andrea Arcangeli wrote: > > I finished the debugging of the ioctl refcounting last week, but I > didn't yet post an update sorry. Great! so we can finally forget this problem ;) > It was important to verify the uffd ctx of the UFFDIO_COPY ioctl is > different than the one registered on the vma where UFFDIO_COPY hits > handle_userfault, I seem to understand... Somehow I thought that __mcopy_atomic() should verify that dst_vma->vm_userfaultfd_ctx.ctx is the same ctx which was used in userfaultfd_ioctl() but it doesn't, it only checks dst_vma->vm_userfaultfd_ctx.ctx != NULL. But why? (I am just curious, let me repeat I know nothing about userfaultfd). Oleg.
