From: Miaohe Lin linmiaohe@huawei.com Subject: mm, slub: fix potential use-after-free in slab_debugfs_fops

When sysfs_slab_add failed, we shouldn't call debugfs_slab_add() for s because s will be freed soon. And slab_debugfs_fops will use s later leading to a use-after-free.

Link: https://lkml.kernel.org/r/20210916123920.48704-5-linmiaohe@huawei.com Fixes: 64dd68497be7 ("mm: slub: move sysfs slab alloc/free interfaces to debugfs") Signed-off-by: Miaohe Lin linmiaohe@huawei.com Reviewed-by: Vlastimil Babka vbabka@suse.cz Cc: Andrey Konovalov andreyknvl@gmail.com Cc: Andrey Ryabinin ryabinin.a.a@gmail.com Cc: Bharata B Rao bharata@linux.ibm.com Cc: Christoph Lameter cl@linux.com Cc: David Rientjes rientjes@google.com Cc: Faiyaz Mohammed faiyazm@codeaurora.org Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Joonsoo Kim iamjoonsoo.kim@lge.com Cc: Kees Cook keescook@chromium.org Cc: Pekka Enberg penberg@kernel.org Cc: Roman Gushchin guro@fb.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/slub.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/mm/slub.c~mm-slub-fix-potential-use-after-free-in-slab_debugfs_fops +++ a/mm/slub.c @@ -4887,13 +4887,15 @@ int __kmem_cache_create(struct kmem_cach return 0;

err = sysfs_slab_add(s); - if (err) + if (err) { __kmem_cache_release(s); + return err; + }

if (s->flags & SLAB_STORE_USER) debugfs_slab_add(s);

- return err; + return 0; }

void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller) _