[PATCH] mm: security: introduce CONFIG_INIT_HEAP_ALL

[Qian Cai]

On Fri, 2019-04-12 at 14:45 +0200, Alexander Potapenko wrote:
> This config option adds the possibility to initialize newly allocated
> pages and heap objects with zeroes. This is needed to prevent possible
> information leaks and make the control-flow bugs that depend on
> uninitialized values more deterministic.
> 
> Initialization is done at allocation time at the places where checks for
> __GFP_ZERO are performed. We don't initialize slab caches with
> constructors or SLAB_TYPESAFE_BY_RCU to preserve their semantics.
> 
> For kernel testing purposes filling allocations with a nonzero pattern
> would be more suitable, but may require platform-specific code. To have
> a simple baseline we've decided to start with zero-initialization.
> 
> No performance optimizations are done at the moment to reduce double
> initialization of memory regions.

Sounds like this has already existed in some degree, i.e.,

CONFIG_PAGE_POISONING_ZERO