From: Catalin Marinas <catalin.marinas@arm.com>
To: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
Andrew Morton <akpm@linux-foundation.org>,
Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Arnd Bergmann <arnd@arndb.de>, Oleg Nesterov <oleg@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
Shuah Khan <shuah@kernel.org>,
"Rick P. Edgecombe" <rick.p.edgecombe@intel.com>,
Deepak Gupta <debug@rivosinc.com>,
Ard Biesheuvel <ardb@kernel.org>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
Kees Cook <kees@kernel.org>, "H.J. Lu" <hjl.tools@gmail.com>,
Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Florian Weimer <fweimer@redhat.com>,
Christian Brauner <brauner@kernel.org>,
Thiago Jung Bauermann <thiago.bauermann@linaro.org>,
Ross Burton <ross.burton@arm.com>,
David Spickett <david.spickett@arm.com>,
Yury Khrustalev <yury.khrustalev@arm.com>,
Wilco Dijkstra <wilco.dijkstra@arm.com>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
kvmarm@lists.linux.dev, linux-fsdevel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org
Subject: Re: [PATCH v13 22/40] arm64/gcs: Ensure that new threads have a GCS
Date: Fri, 4 Oct 2024 14:18:45 +0300 [thread overview]
Message-ID: <Zv_PFVffwIkKevzE@arm.com> (raw)
In-Reply-To: <20241001-arm64-gcs-v13-22-222b78d87eee@kernel.org>
On Tue, Oct 01, 2024 at 11:59:01PM +0100, Mark Brown wrote:
> When a new thread is created by a thread with GCS enabled the GCS needs
> to be specified along with the regular stack.
>
> Unfortunately plain clone() is not extensible and existing clone3()
> users will not specify a stack so all existing code would be broken if
> we mandated specifying the stack explicitly. For compatibility with
> these cases and also x86 (which did not initially implement clone3()
> support for shadow stacks) if no GCS is specified we will allocate one
> so when a thread is created which has GCS enabled allocate one for it.
> We follow the extensively discussed x86 implementation and allocate
> min(RLIMIT_STACK/2, 2G). Since the GCS only stores the call stack and not
> any variables this should be more than sufficient for most applications.
>
> GCSs allocated via this mechanism will be freed when the thread exits.
I think Szabolcs mentioned a GCS leak with v12:
https://lore.kernel.org/r/ZtrihWQFyb2/XrQV@arm.com
(and in some private messages IIRC)
Has this been identified? The changelog only mentions a leak in v8.
--
Catalin
next prev parent reply other threads:[~2024-10-04 11:18 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-10-01 22:58 [PATCH v13 00/40] arm64/gcs: Provide support for GCS in userspace Mark Brown
2024-10-01 22:58 ` [PATCH v13 01/40] mm: Introduce ARCH_HAS_USER_SHADOW_STACK Mark Brown
2024-10-01 22:58 ` [PATCH v13 02/40] mm: Define VM_HIGH_ARCH_6 Mark Brown
2024-10-01 22:58 ` [PATCH v13 03/40] arm64/mm: Restructure arch_validate_flags() for extensibility Mark Brown
2024-10-01 22:58 ` [PATCH v13 04/40] prctl: arch-agnostic prctl for shadow stack Mark Brown
2024-10-01 23:13 ` Deepak Gupta
2024-10-01 22:58 ` [PATCH v13 05/40] mman: Add map_shadow_stack() flags Mark Brown
2024-10-01 22:58 ` [PATCH v13 06/40] arm64: Document boot requirements for Guarded Control Stacks Mark Brown
2024-10-01 22:58 ` [PATCH v13 07/40] arm64/gcs: Document the ABI " Mark Brown
2024-10-01 22:58 ` [PATCH v13 08/40] arm64/sysreg: Add definitions for architected GCS caps Mark Brown
2024-10-01 22:58 ` [PATCH v13 09/40] arm64/gcs: Add manual encodings of GCS instructions Mark Brown
2024-10-01 22:58 ` [PATCH v13 10/40] arm64/gcs: Provide put_user_gcs() Mark Brown
2024-10-01 22:58 ` [PATCH v13 11/40] arm64/gcs: Provide basic EL2 setup to allow GCS usage at EL0 and EL1 Mark Brown
2024-10-09 20:49 ` Nathan Chancellor
2024-10-10 15:18 ` Marc Zyngier
2024-10-10 17:16 ` Catalin Marinas
2024-10-11 12:55 ` Marc Zyngier
2024-10-14 16:31 ` Catalin Marinas
2024-10-15 13:05 ` Catalin Marinas
2024-10-01 22:58 ` [PATCH v13 12/40] arm64/cpufeature: Runtime detection of Guarded Control Stack (GCS) Mark Brown
2024-10-01 22:58 ` [PATCH v13 13/40] arm64/mm: Allocate PIE slots for EL0 guarded control stack Mark Brown
2024-10-01 22:58 ` [PATCH v13 14/40] mm: Define VM_SHADOW_STACK for arm64 when we support GCS Mark Brown
2024-10-01 22:58 ` [PATCH v13 15/40] arm64/mm: Map pages for guarded control stack Mark Brown
2024-10-01 22:58 ` [PATCH v13 16/40] KVM: arm64: Manage GCS access and registers for guests Mark Brown
2024-10-02 0:24 ` Marc Zyngier
2024-10-02 15:55 ` Marc Zyngier
2024-10-02 18:24 ` Mark Brown
2024-10-02 19:29 ` Marc Zyngier
2024-10-03 14:50 ` Mark Brown
2024-10-01 22:58 ` [PATCH v13 17/40] arm64/idreg: Add overrride for GCS Mark Brown
2024-10-01 22:58 ` [PATCH v13 18/40] arm64/hwcap: Add hwcap " Mark Brown
2024-10-03 16:25 ` Yury Khrustalev
2024-10-01 22:58 ` [PATCH v13 19/40] arm64/traps: Handle GCS exceptions Mark Brown
2024-10-01 22:58 ` [PATCH v13 20/40] arm64/mm: Handle GCS data aborts Mark Brown
2024-10-01 22:59 ` [PATCH v13 21/40] arm64/gcs: Context switch GCS state for EL0 Mark Brown
2024-10-01 22:59 ` [PATCH v13 22/40] arm64/gcs: Ensure that new threads have a GCS Mark Brown
2024-10-04 11:18 ` Catalin Marinas [this message]
2024-10-04 11:50 ` Mark Brown
2024-10-01 22:59 ` [PATCH v13 23/40] arm64/gcs: Implement shadow stack prctl() interface Mark Brown
2024-10-01 22:59 ` [PATCH v13 24/40] arm64/mm: Implement map_shadow_stack() Mark Brown
2024-10-01 22:59 ` [PATCH v13 25/40] arm64/signal: Set up and restore the GCS context for signal handlers Mark Brown
2024-10-01 22:59 ` [PATCH v13 26/40] arm64/signal: Expose GCS state in signal frames Mark Brown
2024-10-01 22:59 ` [PATCH v13 27/40] arm64/ptrace: Expose GCS via ptrace and core files Mark Brown
2024-10-01 22:59 ` [PATCH v13 28/40] arm64: Add Kconfig for Guarded Control Stack (GCS) Mark Brown
2024-10-01 22:59 ` [PATCH v13 29/40] kselftest/arm64: Verify the GCS hwcap Mark Brown
2024-10-01 22:59 ` [PATCH v13 30/40] kselftest/arm64: Add GCS as a detected feature in the signal tests Mark Brown
2024-10-01 22:59 ` [PATCH v13 31/40] kselftest/arm64: Add framework support for GCS to signal handling tests Mark Brown
2024-10-01 22:59 ` [PATCH v13 32/40] kselftest/arm64: Allow signals tests to specify an expected si_code Mark Brown
2024-10-01 22:59 ` [PATCH v13 33/40] kselftest/arm64: Always run signals tests with GCS enabled Mark Brown
2024-10-01 22:59 ` [PATCH v13 34/40] kselftest/arm64: Add very basic GCS test program Mark Brown
2024-10-01 22:59 ` [PATCH v13 35/40] kselftest/arm64: Add a GCS test program built with the system libc Mark Brown
2024-10-01 22:59 ` [PATCH v13 36/40] kselftest/arm64: Add test coverage for GCS mode locking Mark Brown
2024-10-01 22:59 ` [PATCH v13 37/40] kselftest/arm64: Add GCS signal tests Mark Brown
2024-10-01 22:59 ` [PATCH v13 38/40] kselftest/arm64: Add a GCS stress test Mark Brown
2024-10-01 22:59 ` [PATCH v13 39/40] kselftest/arm64: Enable GCS for the FP stress tests Mark Brown
2024-10-01 22:59 ` [PATCH v13 40/40] KVM: selftests: arm64: Add GCS registers to get-reg-list Mark Brown
2024-10-04 13:52 ` (subset) [PATCH v13 00/40] arm64/gcs: Provide support for GCS in userspace Catalin Marinas
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