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From: Oliver Upton <oliver.upton@linux.dev>
To: Fuad Tabba <tabba@google.com>
Cc: kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	maz@kernel.org, ankita@nvidia.com, joey.gouly@arm.com,
	suzuki.poulose@arm.com, yuzenghui@huawei.com,
	catalin.marinas@arm.com, will@kernel.org
Subject: Re: [PATCH v1] KVM: arm64: Fix page leak in user_mem_abort()
Message-ID: <aMrgeuZur2Zd6ybX@linux.dev>
References: <20250917130737.2139403-1-tabba@google.com>
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On Wed, Sep 17, 2025 at 02:07:37PM +0100, Fuad Tabba wrote:
> The user_mem_abort() function acquires a page reference via
> __kvm_faultin_pfn() early in its execution. However, the subsequent
> checks for mismatched attributes between stage 1 and stage 2 mappings
> would return an error code directly, bypassing the corresponding page
> release.
> 
> Fix this by storing the error and releasing the unused page before
> returning the error.
> 
> Fixes: 6d674e28f642 ("KVM: arm/arm64: Properly handle faulting of device mappings")
> Fixes: 2a8dfab26677 ("KVM: arm64: Block cacheable PFNMAP mapping")
> Signed-off-by: Fuad Tabba <tabba@google.com>

Yikes, nice catch.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>

Thanks,
Oliver