Breno Leitao <leitao@xxxxxxxxxx> writes: > Add support for KASAN in the alloc_caches (apoll and netmsg_cache). > Thus, if something touches the unused caches, it will raise a KASAN > warning/exception. > > It poisons the object when the object is put to the cache, and unpoisons > it when the object is gotten or freed. > > Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx> > --- > include/linux/io_uring_types.h | 1 + > io_uring/alloc_cache.h | 6 +++++- > io_uring/io_uring.c | 4 ++-- > io_uring/net.h | 5 ++++- > 4 files changed, 12 insertions(+), 4 deletions(-) > > diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h > index efa66b6c32c9..35ebcfb46047 100644 > --- a/include/linux/io_uring_types.h > +++ b/include/linux/io_uring_types.h > @@ -190,6 +190,7 @@ struct io_ev_fd { > struct io_alloc_cache { > struct io_wq_work_node list; > unsigned int nr_cached; > + size_t elem_size; > }; > > struct io_ring_ctx { > diff --git a/io_uring/alloc_cache.h b/io_uring/alloc_cache.h > index 301855e94309..3aba7b356320 100644 > --- a/io_uring/alloc_cache.h > +++ b/io_uring/alloc_cache.h > @@ -16,6 +16,8 @@ static inline bool io_alloc_cache_put(struct io_alloc_cache *cache, > if (cache->nr_cached < IO_ALLOC_CACHE_MAX) { > cache->nr_cached++; > wq_stack_add_head(&entry->node, &cache->list); > + /* KASAN poisons object */ > + kasan_slab_free_mempool(entry); > return true; > } > return false; > @@ -27,6 +29,7 @@ static inline struct io_cache_entry *io_alloc_cache_get(struct io_alloc_cache *c > struct io_cache_entry *entry; > > entry = container_of(cache->list.next, struct io_cache_entry, node); > + kasan_unpoison_range(entry, cache->elem_size); I kind of worry there is no type checking at the same time we are unpoisoning a constant-size range. Seems easy to misuse the API. But it does look much better now with elem_size cached inside io_alloc_cache. > > -#if defined(CONFIG_NET) > struct io_async_msghdr { > +#if defined(CONFIG_NET) > union { > struct iovec fast_iov[UIO_FASTIOV]; > struct { > @@ -22,8 +22,11 @@ struct io_async_msghdr { > struct sockaddr __user *uaddr; > struct msghdr msg; > struct sockaddr_storage addr; > +#endif > }; > > +#if defined(CONFIG_NET) > + Nit, but you could have added an empty definition in the #else section that already exists in the file, or just guarded the caching code entirely when CONFIG_NET=n. Just nits, and overall it is good to have this KASAN support! Reviewed-by: Gabriel Krisman Bertazi <krisman@xxxxxxx> -- Gabriel Krisman Bertazi