Re: [PATCH v2 00/17] x86/ldt: Use a VMA based read only mapping

[Peter Zijlstra]

On Thu, Dec 14, 2017 at 08:35:50AM -0800, Andy Lutomirski wrote:

> > @@ -3252,6 +3256,7 @@ static const struct vm_operations_struct
> >         .fault = special_mapping_fault,
> >         .mremap = special_mapping_mremap,
> >         .name = special_mapping_name,
> > +       .split = special_mapping_split,
> >  };
> >
> >  static const struct vm_operations_struct legacy_special_mapping_vmops = {
> 
> Disallowing splitting seems fine.  Disallowing munmap might not be.
> Certainly CRIU relies on being able to mremap() the VDSO.

And for mremap() we need do_munmap() to work, argh.