Re: [PATCH v2 02/17] mm: Exempt special mappings from mlock(), mprotect() and madvise()

[Peter Zijlstra]

On Thu, Dec 14, 2017 at 08:19:36AM -0800, Andy Lutomirski wrote:
> On Thu, Dec 14, 2017 at 3:27 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> > It makes no sense to ever prod at special mappings with any of these
> > syscalls.
> >
> > XXX should we include munmap() ?
> 
> This is an ABI break for the vdso.  Maybe that's okay, but mremap() on
> the vdso is certainly used, and I can imagine debuggers using
> mprotect().

*groan*, ok so mremap() will actually still work after this, but yes,
mprotect() will not. I hadn't figured people would muck with the VDSO
like that.