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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48512692c14sm13045615e9.7.2026.03.03.01.12.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Mar 2026 01:12:14 -0800 (PST) Date: Tue, 3 Mar 2026 09:12:12 +0000 From: David Laight To: "Christophe Leroy (CS GROUP)" Cc: Alexander Viro , Andre Almeida , Andrew Cooper , Christian Borntraeger , Christian Brauner , Darren Hart , Davidlohr Bueso , Heiko Carstens , Jan Kara , Julia Lawall , Linus Torvalds , linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, LKML , Madhavan Srinivasan , Mathieu Desnoyers , Michael Ellerman , Nicholas Piggin , Nicolas Palix , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Russell King , Sven Schnelle , Thomas Gleixner , x86@kernel.org, Kees Cook , akpm@linux-foundation.org Subject: Re: [PATCH v2 4/5] uaccess: Disable -Wshadow in __scoped_user_access() Message-ID: <20260303091212.620241c8@pumpkin> In-Reply-To: References: <20260302132755.1475451-1-david.laight.linux@gmail.com> <20260302132755.1475451-5-david.laight.linux@gmail.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Mon, 2 Mar 2026 16:00:26 +0100 "Christophe Leroy (CS GROUP)" wrote: > Le 02/03/2026 =C3=A0 14:27, david.laight.linux@gmail.com a =C3=A9crit=C2= =A0: > > From: David Laight > >=20 > > -Wshadow is enabled by W=3D2 builds and __scoped_user_access() quite > > deliberately creates a 'const' shadow of the 'user' address that > > references a 'guard page' when the application passes a kernel pointer. > >=20 > > Signed-off-by: David Laight =20 >=20 > There is a problem with this patch: (badly line-wrapped errors deleted) It seems to need gcc 12. (So Linus is in luck.) Prior to gcc 12 the #pragma generated by _Pragma() act as the controlled statement of the for () loop. Trying to put the _Pragma() inside the for statement doesn't work at all. David