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Date: Mon, 26 Sep 2022 13:22:50 +0200
From: Joerg Roedel <joro@8bytes.org>
To: Vasant Hegde <vasant.hegde@amd.com>
Cc: iommu@lists.linux.dev, robin.murphy@arm.com,
	suravee.suthikulpanit@amd.com
Subject: Re: [PATCH 2/5] iommu/amd: Protect domain update with domain_lock
Message-ID: <YzGLimZhwwt6qIVB@8bytes.org>
References: <20220912063248.7909-1-vasant.hegde@amd.com>
 <20220912063248.7909-3-vasant.hegde@amd.com>
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In-Reply-To: <20220912063248.7909-3-vasant.hegde@amd.com>

Hi Vasant,

On Mon, Sep 12, 2022 at 06:32:45AM +0000, Vasant Hegde wrote:
> In protection_domain_free() path it calls amd_iommu_domain_update() to
> update IOMMU.
>   protection_domain_free -> free_io_pgtable_ops ->
>     v1_free_pgtable -> amd_iommu_domain_update
> 
> Make sure its protected using domain->lock.

A concurrent access to the domain at this point would be a bug in
itself, and the locking wouldn't help here either because the domain
including the lock is freed right after release.

Do you see and concurrent accesses to the domain at this point?

Regards,

	Joerg