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From: Oliver Upton <oupton@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: kvm@vger.kernel.org, kvmarm@lists.linux.dev,
	Steffen Eiden <seiden@linux.ibm.com>,
	Joey Gouly <joey.gouly@arm.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Zenghui Yu <yuzenghui@huawei.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Will Deacon <will@kernel.org>,
	stable@vger.kernel.org
Subject: Re: [PATCH v2] KVM: Move kvm_io_bus_get_dev() locking responsibilities to callers
Date: Sat, 27 Jun 2026 11:14:16 -0700	[thread overview]
Message-ID: <akAS-LN7XZMaZdAQ@kernel.org> (raw)
In-Reply-To: <20260627105105.1005990-1-maz@kernel.org>

On Sat, Jun 27, 2026 at 11:51:05AM +0100, Marc Zyngier wrote:
> kvm_io_bus_get_dev() returns a device that is only matched by the
> address, and nothing else. This can cause a lifetime issue if
> the matched device is not the expected type, as by the time
> the caller can introspect the object, it might be gone (the srcu
> lock having been dropped).
> 
> Given that there is only a single user of this helper, the simplest
> option is to move the locking responsibility to the caller, which
> can keep the srcu lock held for as long as it wants.
> 
> Note that this aligns with other kvm_io_bus*() helpers, which
> already require the srcu lock to be held by the callers.
> 
> Reported-by: Will Deacon <will@kernel.org>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Fixes: 8a39d00670f07 ("KVM: kvm_io_bus: Add kvm_io_bus_get_dev() call")
> Link: https://lore.kernel.org/all/20260626111344.802555-1-maz@kernel.org
> Cc: stable@vger.kernel.org

Thanks for respinning.

Reviewed-by: Oliver Upton <oupton@kernel.org>

      reply	other threads:[~2026-06-27 18:14 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-27 10:51 [PATCH v2] KVM: Move kvm_io_bus_get_dev() locking responsibilities to callers Marc Zyngier
2026-06-27 18:14 ` Oliver Upton [this message]

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