On Mon, Oct 20 2025, Pasha Tatashin wrote: > KHO memory preservation metadata is preserved in 512 byte chunks which > requires their allocation from slab allocator. Slabs are not safe to be > used with KHO because of kfence, and because partial slabs may lead > leaks to the next kernel. Change the size to be PAGE_SIZE. > > The kfence specifically may cause memory corruption, where it randomly > provides slab objects that can be within the scratch area. The reason > for that is that kfence allocates its objects prior to KHO scratch is > marked as CMA region. > > While this change could potentially increase metadata overhead on > systems with sparsely preserved memory, this is being mitigated by > ongoing work to reduce sparseness during preservation via 1G guest > pages. Furthermore, this change aligns with future work on a stateless > KHO, which will also use page-sized bitmaps for its radix tree metadata. > > Signed-off-by: Pasha Tatashin <[email protected]>
Reviewed-by: Pratyush Yadav <[email protected]> [...] -- Regards, Pratyush Yadav
