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[209.85.208.173]) by smtp.gmail.com with ESMTPSA id v10sm571978lji.130.2021.01.14.13.11.28 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 Jan 2021 13:11:29 -0800 (PST) Received: by mail-lj1-f173.google.com with SMTP id n8so8082849ljg.3 for ; Thu, 14 Jan 2021 13:11:28 -0800 (PST) X-Received: by 2002:a2e:6f17:: with SMTP id k23mr3837756ljc.411.1610658688595; Thu, 14 Jan 2021 13:11:28 -0800 (PST) MIME-Version: 1.0 References: <20210114175934.13070-1-will@kernel.org> <20210114175934.13070-5-will@kernel.org> <20210114190021.GB13135@willie-the-truck> <20210114194129.GA13314@willie-the-truck> In-Reply-To: <20210114194129.GA13314@willie-the-truck> From: Linus Torvalds Date: Thu, 14 Jan 2021 13:11:12 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC PATCH 4/8] mm: Separate fault info out of 'struct vm_fault' To: Will Deacon Cc: Nick Desaulniers , Linux Kernel Mailing List , Linux-MM , Linux ARM , Catalin Marinas , Jan Kara , Minchan Kim , Andrew Morton , "Kirill A . Shutemov" , Vinayak Menon , Hugh Dickins , Android Kernel Team Content-Type: text/plain; charset="UTF-8" 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 Thu, Jan 14, 2021 at 11:41 AM Will Deacon wrote: > > Sure enough, an arm64 defconfig builds perfectly alright with that change, > but it really shouldn't. I'm using clang 11.0.5, so I had another go with > GCC 9.2.1 and bang: Ok, looks like a clang bug, but a reasonably benign one. As long as we have sufficient coverage with gcc, we'll get error reporting in a timely manner for any new incorrect assignments, so I think we can do that constant anonymous struct even if it does mean that clang might let some bad cases through (I personally use gcc for build testing, and then clang for building my boot kernels, so I'd catch anything x86-64 allmodconfig in my build tests). And keeping it unnamed it would avoid a lot of noisy churn.. Linus