Function block_phys_has_poison_guard 

pub fn block_phys_has_poison_guard(frame_phys: u64, order: u8) -> bool

Returns true if any page in [phys, phys + 2^order * PAGE_SIZE) has MetaSlot::is_guard_poisoned.

Returns false when the metadata array is not yet initialized (early-boot guard: called from free_list_push / alloc_from_zone during buddy setup before init_metadata_array has run).