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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Tina Zhang <tina.zhang@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Michael Shavit <mshavit@google.com>,
	Vasant Hegde <vasant.hegde@amd.com>,
	"Nicolin Chen ^C-cc=iommu @ lists . linux . dev" 
	<nicolinc@nvidia.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 4/5] iommu: Support mm PASID 1:n with sva domains
Date: Thu, 12 Oct 2023 10:43:10 -0300	[thread overview]
Message-ID: <20231012134310.GI55194@ziepe.ca> (raw)
In-Reply-To: <20231012030112.82270-5-tina.zhang@intel.com>

On Thu, Oct 12, 2023 at 11:01:11AM +0800, Tina Zhang wrote:

> @@ -1188,15 +1193,26 @@ static inline bool tegra_dev_iommu_get_stream_id(struct device *dev, u32 *stream
>  #ifdef CONFIG_IOMMU_SVA
>  static inline void mm_pasid_init(struct mm_struct *mm)
>  {
> -	mm->pasid = IOMMU_PASID_INVALID;
> +	/*
> +	 * During dup_mm(), a new mm will be memcpy'd from an old one and that makes
> +	 * the new mm and the old one point to a same iommu_mm instance. When either
> +	 * one of the two mms gets released, the iommu_mm instance is freed, leaving
> +	 * the other mm running into a use-after-free/double-free problem. To avoid
> +	 * the problem, zeroing the iommu_mm pointer of a new mm is needed here.
> +	 */
> +	mm->iommu_mm = NULL;
>  }

newlines after all the }, between functions doesn't checkpatch
complain?

IMHO this hunk should be moved to the prior patch.

But it all looks good to me now

Thanks,
Jason

  reply	other threads:[~2023-10-12 13:43 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-12  3:01 [PATCH v7 0/5] Share sva domains with all devices bound to a mm Tina Zhang
2023-10-12  3:01 ` [PATCH v7 1/5] iommu/vt-d: Remove mm->pasid in intel_sva_bind_mm() Tina Zhang
2023-10-12  3:01 ` [PATCH v7 2/5] iommu: Add mm_get_enqcmd_pasid() helper function Tina Zhang
2023-10-12  3:01 ` [PATCH v7 3/5] mm: Add structure to keep sva information Tina Zhang
2023-10-12  3:01 ` [PATCH v7 4/5] iommu: Support mm PASID 1:n with sva domains Tina Zhang
2023-10-12 13:43   ` Jason Gunthorpe [this message]
2023-10-13  9:57     ` Zhang, Tina
2023-10-14  0:03       ` Jason Gunthorpe
2023-10-14  1:02         ` Nicolin Chen
2023-10-12  3:01 ` [PATCH v7 5/5] mm: Deprecate pasid field Tina Zhang
2023-10-12  6:14 ` [PATCH v7 0/5] Share sva domains with all devices bound to a mm Nicolin Chen

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