From: Catalin Marinas <catalin.marinas@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Oliver Upton <oupton@kernel.org>,
Lorenzo Pieralisi <lpieralisi@kernel.org>,
Sudeep Holla <sudeep.holla@kernel.org>,
James Morse <james.morse@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
kvmarm@lists.linux.dev
Subject: Re: [PATCH v3 4/5] arm64: errata: Work around early CME DVMSync acknowledgement
Date: Fri, 27 Mar 2026 19:15:31 +0000 [thread overview]
Message-ID: <acbXU2IEi4CPyoqU@arm.com> (raw)
In-Reply-To: <20260323162408.4163113-5-catalin.marinas@arm.com>
On Mon, Mar 23, 2026 at 04:24:04PM +0000, Catalin Marinas wrote:
> +void sme_enable_dvmsync(void)
> +{
> + if ((!cpumask_available(sme_dvmsync_cpus) &&
> + !zalloc_cpumask_var(&sme_dvmsync_cpus, GFP_ATOMIC)) ||
> + (!cpumask_available(sme_active_cpus) &&
> + !zalloc_cpumask_var(&sme_active_cpus, GFP_ATOMIC)))
> + panic("Unable to allocate the cpumasks for SME DVMSync erratum");
> +
> + cpumask_set_cpu(smp_processor_id(), sme_dvmsync_cpus);
> +}
Sashiko (correctly) highlighted a race here. This function, even if the
erratum is a local cpu feature, is still called via stop_machine() on
all active cpus when the non-boot features are initialised. It only
matters if CPUMASK_OFFSTACK is enabled. I'll add a fix, most likely a
lock around this to serialise the cpumask initialisation.
--
Catalin
next prev parent reply other threads:[~2026-03-27 19:15 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-23 16:24 [PATCH v3 0/5] arm64: Work around C1-Pro erratum 4193714 (CVE-2026-0995) Catalin Marinas
2026-03-23 16:24 ` [PATCH v3 1/5] arm64: tlb: Introduce __tlbi_sync_s1ish_{kernel,batch}() for TLB maintenance Catalin Marinas
2026-03-23 16:24 ` [PATCH v3 2/5] arm64: tlb: Pass the corresponding mm to __tlbi_sync_s1ish() Catalin Marinas
2026-03-23 16:24 ` [PATCH v3 3/5] arm64: cputype: Add C1-Pro definitions Catalin Marinas
2026-03-23 16:24 ` [PATCH v3 4/5] arm64: errata: Work around early CME DVMSync acknowledgement Catalin Marinas
2026-03-27 19:15 ` Catalin Marinas [this message]
2026-03-23 16:24 ` [PATCH v3 5/5] KVM: arm64: Add SMC hook for SME dvmsync erratum Catalin Marinas
2026-03-24 10:14 ` Vincent Donnefort
2026-03-24 12:56 ` Catalin Marinas
2026-03-23 17:53 ` [PATCH v3 0/5] arm64: Work around C1-Pro erratum 4193714 (CVE-2026-0995) Mark Rutland
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