On Wed, Mar 17, 2021 at 09:47:40AM +0100, Marco Elver wrote: > Because memblock allocations are registered with kmemleak, the KFENCE > pool was seen by kmemleak as one large object. Later allocations through > kfence_alloc() that were registered with kmemleak via > slab_post_alloc_hook() would then overlap and trigger a warning. > Therefore, once the pool is initialized, we can remove (free) it from > kmemleak again, since it should be treated as allocator-internal and be > seen as "free memory". > > The second problem is that kmemleak is passed the rounded size, and not > the originally requested size, which is also the size of KFENCE objects. > To avoid kmemleak scanning past the end of an object and trigger a > KFENCE out-of-bounds error, fix the size if it is a KFENCE object. > > For simplicity, to avoid a call to kfence_ksize() in > slab_post_alloc_hook() (and avoid new IS_ENABLED(CONFIG_DEBUG_KMEMLEAK) > guard), just call kfence_ksize() in mm/kmemleak.c:create_object(). > > Reported-by: Luis Henriques <lhenriques@xxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Signed-off-by: Marco Elver <elver@xxxxxxxxxx> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
