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[198.145.64.163]) by smtp.gmail.com with ESMTPSA id m7sm236760pjc.54.2021.03.10.13.03.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Mar 2021 13:03:51 -0800 (PST) Date: Wed, 10 Mar 2021 13:03:50 -0800 From: Kees Cook To: Andrey Konovalov Cc: Alexander Potapenko , Thomas Gleixner , Elena Reshetova , the arch/x86 maintainers , Andy Lutomirski , Peter Zijlstra , Catalin Marinas , Will Deacon , Mark Rutland , Alexander Popov , Ard Biesheuvel , Jann Horn , kernel-hardening@lists.openwall.com, linux-hardening@vger.kernel.org, Linux ARM , Linux Memory Management List , LKML , Vlastimil Babka , David Hildenbrand , Mike Rapoport , Andrew Morton , Jonathan Corbet , Randy Dunlap Subject: Re: [PATCH v5 3/7] init_on_alloc: Unpessimize default-on builds Message-ID: <202103101303.6E6569C1@keescook> References: <20210309214301.678739-1-keescook@chromium.org> <20210309214301.678739-4-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6F94C4080F40 X-Stat-Signature: ywwgk1zfae83btx5qp67aedikm8axepz Received-SPF: none (chromium.org>: No applicable sender policy available) receiver=imf17; identity=mailfrom; envelope-from=""; helo=mail-pf1-f172.google.com; client-ip=209.85.210.172 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1615410232-91454 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Mar 10, 2021 at 01:52:04PM +0100, Andrey Konovalov wrote: > On Tue, Mar 9, 2021 at 10:43 PM Kees Cook wrote: > > > > Right now, the state of CONFIG_INIT_ON_ALLOC_DEFAULT_ON (and > > ...ON_FREE...) did not change the assembly ordering of the static branch > > tests. Use the new jump_label macro to check CONFIG settings to default > > to the "expected" state, unpessimizes the resulting assembly code. > > > > Reviewed-by: Alexander Potapenko > > Link: https://lore.kernel.org/lkml/CAG_fn=X0DVwqLaHJTO6Jw7TGcMSm77GKHinrd0m_6y0SzWOrFA@mail.gmail.com/ > > Signed-off-by: Kees Cook > > --- > > include/linux/mm.h | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/include/linux/mm.h b/include/linux/mm.h > > index bf341a9bfe46..2ccd856ac0d1 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -2874,7 +2874,8 @@ static inline void kernel_unpoison_pages(struct page *page, int numpages) { } > > DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, init_on_alloc); > > static inline bool want_init_on_alloc(gfp_t flags) > > { > > - if (static_branch_unlikely(&init_on_alloc)) > > + if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, > > + &init_on_alloc)) > > return true; > > return flags & __GFP_ZERO; > > } > > @@ -2882,7 +2883,8 @@ static inline bool want_init_on_alloc(gfp_t flags) > > DECLARE_STATIC_KEY_MAYBE(CONFIG_INIT_ON_FREE_DEFAULT_ON, init_on_free); > > static inline bool want_init_on_free(void) > > { > > - return static_branch_unlikely(&init_on_free); > > + return static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, > > + &init_on_free); > > } > > > > extern bool _debug_pagealloc_enabled_early; > > Should we also update slab_want_init_on_alloc() and slab_want_init_on_free()? Whoops! Thank you; I will update and resend. :) -- Kees Cook