Re: vdso && f_op->mremap (Was: special_mapping_fault() is broken)

Andy Lutomirski
2015-06-23T01:27:16Z

On Mon, Jun 22, 2015 at 5:47 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 06/21, Oleg Nesterov wrote:
>>
>> Forgot to add Andy...
>
> Add Pavel ;)
>
> I never understood why ->mremap() lives in file_operations, not in
> vm_operations_struct. To me vma->vm_file->f_op in move_vma() just
> looks strange, vma->vm_ops->mremap(new_vma) looks "obviously better".
>
> And afaics more useful. CRIU remaps vdso, but this does not update
> mm->context.vdso. OK, probably this does not matter currently, CRIU
> can't c/r the compat tasks, and 64-bit apps do not use context.vdso.
> Afaics. Still, I think we might want to have special_mapping_remap()
> and we can't do this because ->vm_file == NULL.

I would like this. Then I could clean up and resubmit my patch to
keep context.vdso up to date.

Oleg, can you let me know what patch, if any, I should be reviewing?

--Andy