From: David Laight <david.laight.linux@gmail.com>
To: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andre Almeida <andrealmeid@igalia.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Christian Brauner <brauner@kernel.org>,
Darren Hart <dvhart@infradead.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Heiko Carstens <hca@linux.ibm.com>, Jan Kara <jack@suse.cz>,
Julia Lawall <Julia.Lawall@inria.fr>,
Linus Torvalds <torvalds@linux-foundation.org>,
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 <linux-kernel@vger.kernel.org>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Nicolas Palix <nicolas.palix@imag.fr>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <pjw@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Russell King <linux@armlinux.org.uk>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Kees Cook <kees@kernel.org>,
akpm@linux-foundation.org
Subject: Re: [PATCH v2 4/5] uaccess: Disable -Wshadow in __scoped_user_access()
Date: Tue, 3 Mar 2026 09:12:12 +0000 [thread overview]
Message-ID: <20260303091212.620241c8@pumpkin> (raw)
In-Reply-To: <e54368a9-9118-476d-b999-bcd60847f0ce@kernel.org>
On Mon, 2 Mar 2026 16:00:26 +0100
"Christophe Leroy (CS GROUP)" <chleroy@kernel.org> wrote:
> Le 02/03/2026 à 14:27, david.laight.linux@gmail.com a écrit :
> > From: David Laight <david.laight.linux@gmail.com>
> >
> > -Wshadow is enabled by W=2 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.
> >
> > Signed-off-by: David Laight <david.laight.linux@gmail.com>
>
> 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
WARNING: multiple messages have this Message-ID (diff)
From: David Laight <david.laight.linux@gmail.com>
To: "Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andre Almeida <andrealmeid@igalia.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Christian Brauner <brauner@kernel.org>,
Darren Hart <dvhart@infradead.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Heiko Carstens <hca@linux.ibm.com>, Jan Kara <jack@suse.cz>,
Julia Lawall <Julia.Lawall@inria.fr>,
Linus Torvalds <torvalds@linux-foundation.org>,
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 <linux-kernel@vger.kernel.org>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Nicolas Palix <nicolas.palix@imag.fr>,
Palmer Dabbelt <palmer@dabbelt.com>,
Paul Walmsley <pjw@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Russell King <linux@armlinux.org.uk>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
x86@kernel.org, Kees Cook <kees@kernel.org>,
akpm@linux-foundation.org
Subject: Re: [PATCH v2 4/5] uaccess: Disable -Wshadow in __scoped_user_access()
Date: Tue, 3 Mar 2026 09:12:12 +0000 [thread overview]
Message-ID: <20260303091212.620241c8@pumpkin> (raw)
In-Reply-To: <e54368a9-9118-476d-b999-bcd60847f0ce@kernel.org>
On Mon, 2 Mar 2026 16:00:26 +0100
"Christophe Leroy (CS GROUP)" <chleroy@kernel.org> wrote:
> Le 02/03/2026 à 14:27, david.laight.linux@gmail.com a écrit :
> > From: David Laight <david.laight.linux@gmail.com>
> >
> > -Wshadow is enabled by W=2 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.
> >
> > Signed-off-by: David Laight <david.laight.linux@gmail.com>
>
> 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
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next prev parent reply other threads:[~2026-03-03 9:12 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-02 13:27 [PATCH v2 0/5] uaccess: Updates to scoped_user_access() david.laight.linux
2026-03-02 13:27 ` david.laight.linux
2026-03-02 13:27 ` [PATCH v2 1/5] uaccess: Fix scoped_user_read_access() for 'pointer to const' david.laight.linux
2026-03-02 13:27 ` david.laight.linux
2026-03-02 14:59 ` Christophe Leroy (CS GROUP)
2026-03-02 14:59 ` Christophe Leroy (CS GROUP)
2026-03-02 17:26 ` Linus Torvalds
2026-03-02 17:26 ` Linus Torvalds
2026-03-02 18:55 ` David Laight
2026-03-02 18:55 ` David Laight
2026-03-02 13:27 ` [PATCH v2 2/5] compiler.h: Add generic support for 'autoterminating nested for() loops' david.laight.linux
2026-03-02 13:27 ` david.laight.linux
2026-03-02 13:27 ` [PATCH v2 3/5] uaccess.h: Use with() and and_with() in __scoped_user_access() david.laight.linux
2026-03-02 13:27 ` david.laight.linux
2026-03-02 13:27 ` [PATCH v2 4/5] uaccess: Disable -Wshadow " david.laight.linux
2026-03-02 13:27 ` david.laight.linux
2026-03-02 15:00 ` Christophe Leroy (CS GROUP)
2026-03-02 15:00 ` Christophe Leroy (CS GROUP)
2026-03-03 9:12 ` David Laight [this message]
2026-03-03 9:12 ` David Laight
2026-03-02 17:17 ` Linus Torvalds
2026-03-02 17:17 ` Linus Torvalds
2026-03-05 8:10 ` kernel test robot
2026-03-05 8:10 ` kernel test robot
2026-03-02 13:27 ` [PATCH v2 next 5/5] signal: Use scoped_user_access() instead of __put/get_user() david.laight.linux
2026-03-02 13:27 ` david.laight.linux
2026-03-02 16:07 ` Christophe Leroy (CS GROUP)
2026-03-02 16:07 ` Christophe Leroy (CS GROUP)
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