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Date:   Thu, 28 Apr 2022 10:18:29 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     cgel.zte@gmail.com
Cc:     will@kernel.org, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, Lv Ruyi <lv.ruyi@zte.com.cn>,
        Zeal Robot <zealci@zte.com.cn>
Subject: Re: [PATCH] iommu: add null pointer check
Message-ID: <YmpN1ZVZMrU9ZJ3e@8bytes.org>
References: <20220329055322.2375563-1-lv.ruyi@zte.com.cn>
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On Tue, Mar 29, 2022 at 05:53:22AM +0000, cgel.zte@gmail.com wrote:
> From: Lv Ruyi <lv.ruyi@zte.com.cn>
> 
> kmem_cache_zalloc is a memory allocation function which can return NULL
> when some internal memory errors happen. Add null pointer check to avoid
> dereferencing null pointer.
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
> ---
>  drivers/iommu/fsl_pamu_domain.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/iommu/fsl_pamu_domain.c b/drivers/iommu/fsl_pamu_domain.c
> index 69a4a62dc3b9..43849c027298 100644
> --- a/drivers/iommu/fsl_pamu_domain.c
> +++ b/drivers/iommu/fsl_pamu_domain.c
> @@ -152,6 +152,10 @@ static void attach_device(struct fsl_dma_domain *dma_domain, int liodn, struct d
>  	}
>  
>  	info = kmem_cache_zalloc(iommu_devinfo_cache, GFP_ATOMIC);
> +	if (!info) {
> +		spin_unlock_irqrestore(&device_domain_lock, flags);
> +		return;
> +	}

Such errors need to be propagated.