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Date:   Thu, 21 May 2020 11:49:06 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Prakash Gupta <guptap@codeaurora.org>
Cc:     mhocko@suse.com, joro@8bytes.org, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] iommu/dma: limit iova free size to unmmaped iova
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On Thu, 21 May 2020 17:00:04 +0530 Prakash Gupta <guptap@codeaurora.org> wrote:

> Limit the iova size while freeing based on unmapped size. In absence of
> this even with unmap failure, invalid iova is pushed to iova rcache and
> subsequently can cause panic while rcache magazine is freed.
> 
> Signed-off-by: Prakash Gupta <guptap@codeaurora.org>
> 

I think we need a cc:stable here?

> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -472,7 +472,8 @@ static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,
>  
>  	if (!cookie->fq_domain)
>  		iommu_tlb_sync(domain, &iotlb_gather);
> -	iommu_dma_free_iova(cookie, dma_addr, size);
> +	if (unmapped)
> +		iommu_dma_free_iova(cookie, dma_addr, unmapped);
>  }
>  
>  static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,

I'll assume that Joerg will handle this fix?