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[81.154.179.160]) by smtp.gmail.com with ESMTPSA id a2-20020a5d53c2000000b002ffbf2213d4sm13537164wrw.75.2023.05.24.00.15.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 24 May 2023 00:15:23 -0700 (PDT) Date: Wed, 24 May 2023 08:15:23 +0100 From: Lorenzo Stoakes To: David Hildenbrand Cc: Vlastimil Babka , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Roman Gushchin , Hyeonggon Yoo <42.hyeyoo@gmail.com>, Kees Cook , linux-mm@kvack.org, linux-hardening@vger.kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/slab: remove HAVE_HARDENED_USERCOPY_ALLOCATOR Message-ID: References: <20230523073136.4900-1-vbabka@suse.cz> <310077ed-6f3f-41fe-afcf-36500a9408ec@lucifer.local> <623a87c6-c0d2-799a-c39e-0d14dcdfa6df@suse.cz> <4674f97f-5f97-45b7-a4b9-a19ca46b7ce1@lucifer.local> <9191d9b0-3318-4e70-a81b-69acff184fc6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9191d9b0-3318-4e70-a81b-69acff184fc6@redhat.com> X-Rspamd-Queue-Id: E30B74000E X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: y5ydt9otyyysywuugqqfo4skwxrfsibb X-HE-Tag: 1684912526-542250 X-HE-Meta: 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 HoNwaYAI YIMCtPDBi/tweJ+OL+kUknyRAK7WpTwBViZ+DmKjqqgxa13mr5cLIk/ZjIWecYqN2Brkdri7qTkyCospaybNOvA/S4IYiHl0MXuURiTP0MsmjStSQhej/zKsWvTV42hsA51Q00aKlojquUj3s5tX/UtbwBQ5/CNGglIF+GSeNfW+BhPUQbgH3RKKssJU4lKWFUvXoIzP2J6DcGF4du1WR3eV8y5cgcrhJ96QtIyHXRTF+ArI8A5vhcLEd1ds+Vhnqlm+ERig/xVtma1SNaCOt0B9GN/vU1Vd/5jNiVEhoyFnfM+ERxL8ABUFfJoXMIIptrNLAQyLSYglJbE3NoLOoimTUW2OJ4F/+MtY7UV9610AqjBKdpVSVKUkT8JXa0LKUrk2kfJhKdJgvkkXCqiTGIfYaXKmC10oSfJ0ZyarqdvajDSt0ernycrHQSGOTqfwVEwsG3+fm+eaYV84afkvCDMJJG8KyAbSsbNZrn/ugunDa0WzwBBVY97xYaWtoAE8fhRA2U1P6mpNpvNxWyjFsqnDXrg== 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 Tue, May 23, 2023 at 10:28:32AM +0200, David Hildenbrand wrote: [snip] > > > The file is only compiled with CONFIG_HARDENED_USERCOPY: > > > > > > mm/Makefile:obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o > > > > > > > Yeah ugh at this sort of implicit thing. Anyway it'd be preferable to stick > > #ifdef CONFIG_HARDENED_USERCOPY around the prototype just so it's > > abundantly clear this function doesn't exist unless that is set. > > I recall that it is very common to not use ifdefs unless really required. > Because less ifefs are obviously preferable ;) > > Compilation+linking will fail in any case. > I don't want to insist so hard on something that doesn't really matter, the bike shed can be blue, green or red it's fine :P So, Reviewed-by: Lorenzo Stoakes