On Tue, May 17, 2022 at 09:47:13AM -0700, Kristen Carlson Accardi wrote: > [...] > +int sgx_encl_alloc_backing(struct sgx_encl *encl, unsigned long page_index, > + struct sgx_backing *backing) > +{ > + struct mem_cgroup *old_memcg; > + int ret; > + > + old_memcg = sgx_encl_set_active_memcg(encl); This function is leaking memcg reference. Please change sgx_encl_set_active_memcg() to sgx_encl_get_mem_cgroup() or something which will return the memcg with the refcount elevated. Then use set_active_memcg(returned_memcg) here. > + > + ret = sgx_encl_get_backing(encl, page_index, backing); > + > + set_active_memcg(old_memcg); mem_cgroup_put(returned_memcg) here. > + > + return ret; > +}