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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id s194sm14685269pfs.57.2021.03.15.15.15.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Mar 2021 15:15:28 -0700 (PDT) Date: Mon, 15 Mar 2021 15:15:27 -0700 From: Kees Cook To: Thomas Gleixner Cc: Alexander Potapenko , Elena Reshetova , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Popov , Ard Biesheuvel , Jann Horn , Vlastimil Babka , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 2/6] init_on_alloc: Optimize static branches Message-ID: <202103151514.AE11A69683@keescook> References: <20210315180229.1224655-1-keescook@chromium.org> <20210315180229.1224655-3-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210315180229.1224655-3-keescook@chromium.org> Precedence: bulk List-ID: X-Mailing-List: linux-hardening@vger.kernel.org On Mon, Mar 15, 2021 at 11:02:25AM -0700, Kees Cook wrote: > diff --git a/mm/slab.h b/mm/slab.h > index 076582f58f68..b0977d525c06 100644 > --- a/mm/slab.h > +++ b/mm/slab.h > @@ -601,7 +601,8 @@ static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { } > > static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) > { > - if (static_branch_unlikely(&init_on_alloc)) { > + if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, Gah, this should be CONFIG_INIT_ON_ALLOC_DEFAULT_ON. I'll see if there are any more comments before sending a v7... -Kees > + &init_on_alloc)) { > if (c->ctor) > return false; > if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) > @@ -613,7 +614,8 @@ static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) > > static inline bool slab_want_init_on_free(struct kmem_cache *c) > { > - if (static_branch_unlikely(&init_on_free)) > + if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, > + &init_on_free)) > return !(c->ctor || > (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))); > return false; > -- > 2.25.1 > -- Kees Cook