From: Catalin Marinas <catalin.marinas@arm.com>
To: Oleg Nesterov <oleg@redhat.com>, Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Breno Leitao <leitao@debian.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH] arm64/fpsimd: ptrace: zero target's fpsimd_state, not the tracer's
Date: Wed, 6 May 2026 12:17:11 +0100 [thread overview]
Message-ID: <177806623190.3110399.5860608019820883086.b4-ty@arm.com> (raw)
In-Reply-To: <20260505-fix_ptrace-v1-1-36ac1f6d0bfb@debian.org>
On Tue, 05 May 2026 09:02:13 -0700, Breno Leitao wrote:
> sve_set_common() is the backend for PTRACE_SETREGSET(NT_ARM_SVE) and
> PTRACE_SETREGSET(NT_ARM_SSVE). Every write in the function operates on
> the tracee (target) - except a single memset that uses current instead,
> zeroing the tracer's saved V0-V31 / FPSR / FPCR shadow on every ptrace
> SETREGSET call.
>
> The memset is meant to give the tracee a defined zero register image
> before the user-supplied payload is copied in (for partial writes,
> header-only writes, and FPSIMD<->SVE format switches). Aiming it at
> current both denies the tracee that clean slate and silently corrupts
> the tracer.
>
> [...]
Applied to arm64 (for-next/fixes). Also fixed the commit log and added
cc stable. Thanks!
[1/1] arm64/fpsimd: ptrace: zero target's fpsimd_state, not the tracer's
https://git.kernel.org/arm64/c/5cbb61bf4168
prev parent reply other threads:[~2026-05-06 11:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-05 16:02 [PATCH] arm64/fpsimd: ptrace: zero target's fpsimd_state, not the tracer's Breno Leitao
2026-05-05 17:05 ` Mark Rutland
2026-05-06 9:19 ` Breno Leitao
2026-05-06 11:17 ` Catalin Marinas [this message]
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