On 11/02/2019 21:59, Andrey Konovalov wrote: > Right now we call kmemleak hooks before assigning tags to pointers in > KASAN hooks. As a result, when an objects gets allocated, kmemleak sees > a differently tagged pointer, compared to the one it sees when the object > gets freed. Fix it by calling KASAN hooks before kmemleak's ones. >
Nit: Could you please add comments to the the code? It should prevent that the code gets refactored in future, reintroducing the same issue. > Reported-by: Qian Cai <c...@lca.pw> > Signed-off-by: Andrey Konovalov <andreyk...@google.com> > --- > mm/slab.h | 6 ++---- > mm/slab_common.c | 2 +- > mm/slub.c | 3 ++- > 3 files changed, 5 insertions(+), 6 deletions(-) > > diff --git a/mm/slab.h b/mm/slab.h > index 4190c24ef0e9..638ea1b25d39 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -437,11 +437,9 @@ static inline void slab_post_alloc_hook(struct > kmem_cache *s, gfp_t flags, > > flags &= gfp_allowed_mask; > for (i = 0; i < size; i++) { > - void *object = p[i]; > - > - kmemleak_alloc_recursive(object, s->object_size, 1, > + p[i] = kasan_slab_alloc(s, p[i], flags); > + kmemleak_alloc_recursive(p[i], s->object_size, 1, > s->flags, flags); > - p[i] = kasan_slab_alloc(s, object, flags); > } > > if (memcg_kmem_enabled()) > diff --git a/mm/slab_common.c b/mm/slab_common.c > index 81732d05e74a..fe524c8d0246 100644 > --- a/mm/slab_common.c > +++ b/mm/slab_common.c > @@ -1228,8 +1228,8 @@ void *kmalloc_order(size_t size, gfp_t flags, unsigned > int order) > flags |= __GFP_COMP; > page = alloc_pages(flags, order); > ret = page ? page_address(page) : NULL; > - kmemleak_alloc(ret, size, 1, flags); > ret = kasan_kmalloc_large(ret, size, flags); > + kmemleak_alloc(ret, size, 1, flags); > return ret; > } > EXPORT_SYMBOL(kmalloc_order); > diff --git a/mm/slub.c b/mm/slub.c > index 1e3d0ec4e200..4a3d7686902f 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -1374,8 +1374,9 @@ static inline void dec_slabs_node(struct kmem_cache *s, > int node, > */ > static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t > flags) > { > + ptr = kasan_kmalloc_large(ptr, size, flags); > kmemleak_alloc(ptr, size, 1, flags); > - return kasan_kmalloc_large(ptr, size, flags); > + return ptr; > } > > static __always_inline void kfree_hook(void *x) > -- Regards, Vincenzo