On Fri, Jul 26, 2024 at 3:52 PM Jann Horn <jannh@xxxxxxxxxx> wrote: > > > Do we still need this patch? > > I just tried removing this patch from the series; without it, the > kmem_cache_invalid_free kunit test fails because the kmem_cache_free() > no longer synchronously notices that the pointer is misaligned. I > guess I could change the testcase like this to make the tests pass > without this patch, but I'd like to hear from you or another KASAN > person whether you think that's a reasonable change: Ah, I see. I think detecting a bug earlier if we can is better. So I don't mind keeping this patch, was just confused by the commit message. Adding on top of my comments from before: I think if you move check_slab_free() out of poison_slab_object() (but add to __kasan_mempool_poison_object()), and move is_kfence_address() and kasan_arch_is_ready() to poison_slab_object()'s callers, you won't even need the free_validation_result enum, so the patch should become simpler. You can also rename check_slab_free() to check_slab_allocation() to make it be named similarly to the already existing check_page_allocation(). (I think we should also later move kasan_arch_is_ready() out of check_page_allocation() into the high-level hooks for consistency; it also seems cleaner to have all of these ignore checks in the high-level functions instead of lower-level inlined ones.) Thanks!
