linux-kernel - Re: [PATCH] IOMMU: iommu module do not check NULL return of kmem_cache

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Message-ID: <20140304154117.GF2799@8bytes.org>
Date:	Tue, 4 Mar 2014 16:41:18 +0100
From:	Joerg Roedel <joro@...tes.org>
To:	Zhouyi Zhou <zhouzhouyi@...il.com>
Cc:	iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
	Zhouyi Zhou <yizhouzhou@....ac.cn>
Subject: Re: [PATCH] IOMMU: iommu module do not check NULL return of
 kmem_cache_zalloc

On Tue, Feb 11, 2014 at 10:12:53AM +0800, Zhouyi Zhou wrote:
> From: Zhouyi Zhou <yizhouzhou@....ac.cn>
> 
> The function iopte_alloc do not check NULL return of kmem_cache_zalloc,
> call iopte_free with argument 0 will panic.
> 
> Signed-off-by: Zhouyi Zhou <yizhouzhou@....ac.cn>
> ---
>  drivers/iommu/omap-iommu.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/omap-iommu.c b/drivers/iommu/omap-iommu.c
> index bcd78a7..5155714 100644
> --- a/drivers/iommu/omap-iommu.c
> +++ b/drivers/iommu/omap-iommu.c
> @@ -551,7 +551,8 @@ static u32 *iopte_alloc(struct omap_iommu *obj, u32 *iopgd, u32 da)
>  		dev_vdbg(obj->dev, "%s: a new pte:%p\n", __func__, iopte);
>  	} else {
>  		/* We raced, free the reduniovant table */
> -		iopte_free(iopte);
> +		if (iopte)
> +			iopte_free(iopte);

Isn't it better to put the check into iopte_free?


	Joerg


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