On Sat, 10 Feb 2024 at 00:13, Oscar Salvador <osalvador@xxxxxxx> wrote: > > On Fri, Feb 09, 2024 at 10:52:48PM +0100, Oscar Salvador wrote: > > Thinking about it some more, I think I made a mistake: > > > > I am walking all buckets, and within those buckets there are not only > > page_owner stack_records, which means that I could return a stack_record > > from e.g: KASAN (which I think can evict stack_records) and then > > everything goes off the rails. > > Which means I cannot walk the buckets like that. > > > > Actually, I think that having something like the following > > > > struct list_stack_records { > > struct stack_record *stack; > > struct list_stack_records *next; > > } > > Or, I could use the extra_bits field from handle_parts to flag that > when a depot_stack_handle_t is used by page_owner. > > Then __stack_depot_get_next_stack_record() would check whether > a stack_record->handle.extra_bits has the page_owner bit, and only > return those stacks that have such bit. > This would solve the problem of returning a potentially evictable stack > , only by returning page_owner's stack_records, and I would not have > to maintain my own list. > > I yet have to see how that would look like, but sounds promising. > Do you think that is feasible Marco? The extra bits are used by KMSAN, and might conflict if enabled at the same time. I think the safest option is to keep your own list. I think that will also be more performant if there are other stackdepot users because you do not have to traverse any of the other entries.