From: Will Deacon <will@kernel.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
kernel-team@android.com, Michael Ellerman <mpe@ellerman.id.au>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Segher Boessenkool <segher@kernel.crashing.org>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Arnd Bergmann <arnd@arndb.de>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Masahiro Yamada <masahiroy@kernel.org>,
Nick Desaulniers <ndesaulniers@google.com>,
Robin Murphy <robin.murphy@arm.com>
Subject: Re: [PATCH v4 05/11] arm64: csum: Disable KASAN for do_csum()
Date: Wed, 22 Apr 2020 11:41:38 +0100 [thread overview]
Message-ID: <20200422104138.GA30265@willie-the-truck> (raw)
In-Reply-To: <20200422094951.GA54428@lakrids.cambridge.arm.com>
On Wed, Apr 22, 2020 at 10:49:52AM +0100, Mark Rutland wrote:
> On Tue, Apr 21, 2020 at 04:15:31PM +0100, Will Deacon wrote:
> > do_csum() over-reads the source buffer and therefore abuses
> > READ_ONCE_NOCHECK() to avoid tripping up KASAN. In preparation for
> > READ_ONCE_NOCHECK() becoming a macro, and therefore losing its
> > '__no_sanitize_address' annotation, just annotate do_csum() explicitly
> > and fall back to normal loads.
> >
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Cc: Robin Murphy <robin.murphy@arm.com>
> > Signed-off-by: Will Deacon <will@kernel.org>
>
> From a functional perspective:
>
> Acked-by: Mark Rutland <mark.rutland@arm.com>
Thanks.
> I know that Robin had a concern w.r.t. how this would affect the
> codegen, but I think we can follow that up after the series as a whole
> is merged.
Makes sense. I did look at the codegen, fwiw, and it didn't seem especially
bad. One of the LDP's gets cracked in the unlikely() path, but it didn't
look like it would be a disaster (and sprinkling barrier() around to force
the LDP felt really fragile!).
Will
next prev parent reply other threads:[~2020-04-22 10:41 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 15:15 [PATCH v4 00/11] Rework READ_ONCE() to improve codegen Will Deacon
2020-04-21 15:15 ` [PATCH v4 01/11] compiler/gcc: Raise minimum GCC version for kernel builds to 4.8 Will Deacon
2020-04-21 17:15 ` Masahiro Yamada
2020-04-21 15:15 ` [PATCH v4 02/11] netfilter: Avoid assigning 'const' pointer to non-const pointer Will Deacon
2020-04-21 15:15 ` [PATCH v4 03/11] net: tls: " Will Deacon
2020-04-21 15:15 ` [PATCH v4 04/11] fault_inject: Don't rely on "return value" from WRITE_ONCE() Will Deacon
2020-04-21 15:15 ` [PATCH v4 05/11] arm64: csum: Disable KASAN for do_csum() Will Deacon
2020-04-21 15:15 ` Will Deacon
2020-04-22 9:49 ` Mark Rutland
2020-04-22 9:49 ` Mark Rutland
2020-04-22 10:41 ` Will Deacon [this message]
2020-04-22 11:01 ` Robin Murphy
2020-04-24 9:41 ` David Laight
2020-04-24 11:00 ` Robin Murphy
2020-04-24 13:04 ` David Laight
2020-04-24 13:04 ` David Laight
2020-04-21 15:15 ` [PATCH v4 06/11] READ_ONCE: Simplify implementations of {READ,WRITE}_ONCE() Will Deacon
2020-04-21 15:15 ` Will Deacon
2020-04-22 9:51 ` Mark Rutland
2020-04-21 15:15 ` [PATCH v4 07/11] READ_ONCE: Enforce atomicity for {READ,WRITE}_ONCE() memory accesses Will Deacon
2020-04-21 15:15 ` Will Deacon
2020-04-24 16:31 ` Jann Horn
2020-04-24 17:11 ` Will Deacon
2020-04-24 17:43 ` Peter Zijlstra
2020-04-21 15:15 ` [PATCH v4 08/11] READ_ONCE: Drop pointer qualifiers when reading from scalar types Will Deacon
2020-04-21 15:15 ` Will Deacon
2020-04-22 10:25 ` Rasmus Villemoes
2020-04-22 11:48 ` Segher Boessenkool
2020-04-22 11:48 ` Segher Boessenkool
2020-04-22 13:11 ` Will Deacon
2020-04-22 13:11 ` Will Deacon
2020-04-22 14:54 ` Will Deacon
2020-04-21 15:15 ` [PATCH v4 09/11] locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros Will Deacon
2020-04-21 15:15 ` Will Deacon
2020-04-21 15:15 ` [PATCH v4 10/11] arm64: barrier: Use '__unqual_scalar_typeof' for acquire/release macros Will Deacon
2020-04-21 15:15 ` [PATCH v4 11/11] gcov: Remove old GCC 3.4 support Will Deacon
2020-04-21 15:15 ` Will Deacon
2020-04-21 17:19 ` Masahiro Yamada
2020-04-21 18:42 ` [PATCH v4 00/11] Rework READ_ONCE() to improve codegen Linus Torvalds
2020-04-21 18:42 ` Linus Torvalds
2020-04-22 8:18 ` Will Deacon
2020-04-22 11:37 ` Peter Zijlstra
2020-04-22 12:26 ` Will Deacon
2020-04-24 13:42 ` Will Deacon
2020-04-24 15:54 ` Marco Elver
2020-04-24 16:52 ` Will Deacon
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