[RFC] malloc: add random offset to mmapped memory

[Rich Felker]

On Sat, Jan 24, 2015 at 10:01:31PM +0100, Maarten Bosmans wrote:
> My proposal is to use the extra (unused) space that we get from mmap
> anyway (because it is page-aligned) to add an offset to the returned
> pointer. This would improve the performance of this example test case
> when the arrays are large enough to be mmapped directly.
> 
> I would like to get some feedback whether glibc developers think this
> is a worthwhile goal to pursue, before I start working on a patch.

I think you should be cautious not to introduce random perturbations
like this into programs where ASLR has been intentionally disabled. It
makes debugging certain types of issues extremely difficult.

Rich