On Fri, 12 Apr 2019, Alexander Potapenko wrote: > diff --git a/mm/slab.h b/mm/slab.h > index 43ac818b8592..4bb10af0031b 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -167,6 +167,16 @@ static inline slab_flags_t kmem_cache_flags(unsigned int object_size, > SLAB_TEMPORARY | \ > SLAB_ACCOUNT) > > +/* > + * Do we need to initialize this allocation? > + * Always true for __GFP_ZERO, CONFIG_INIT_HEAP_ALL enforces initialization > + * of caches without constructors and RCU. > + */ > +#define SLAB_WANT_INIT(cache, gfp_flags) \ > + ((GFP_INIT_ALWAYS_ON && !(cache)->ctor && \ > + !((cache)->flags & SLAB_TYPESAFE_BY_RCU)) || \ > + (gfp_flags & __GFP_ZERO)) This is another complex thing to maintain when adding flags to the slab allocator. > +config INIT_HEAP_ALL > + bool "Initialize kernel heap allocations" "Zero pages and objects allocated in the kernel" > + default n > + help > + Enforce initialization of pages allocated from page allocator > + and objects returned by kmalloc and friends. > + Allocated memory is initialized with zeroes, preventing possible > + information leaks and making the control-flow bugs that depend > + on uninitialized values more deterministic. Hmmm... But we already have debugging options that poison objects and pages?
