linux-kernel - Re: [PATCH v2] USB: whci-hcd: add more checks for dma mapping error

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Date:	Wed, 30 Mar 2016 10:48:34 +0300
From:	Vladimir Zapolskiy <vz@...ia.com>
To:	Alexey Khoroshilov <khoroshilov@...ras.ru>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	ldv-project@...uxtesting.org
Subject: Re: [PATCH v2] USB: whci-hcd: add more checks for dma mapping error

Hi Alexey,

On 26.03.2016 21:42, Alexey Khoroshilov wrote:
> Fixing checks for dma mapping error in qset_fill_page_list(),
> I have missed two similar problems in qset_add_urb_sg() and
> in qset_add_urb_sg_linearize().
> 
> v2: check validity of dma_addr with dma_mapping_error()
> in qset_free_std() as suggested by Vladimir Zapolskiy.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Signed-off-by: Alexey Khoroshilov <khoroshilov@...ras.ru>

Reviewed-by: Vladimir Zapolskiy <vz@...ia.com>

> ---
>  drivers/usb/host/whci/qset.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/usb/host/whci/qset.c b/drivers/usb/host/whci/qset.c
> index 1a8e960d073b..c0e6812426b3 100644
> --- a/drivers/usb/host/whci/qset.c
> +++ b/drivers/usb/host/whci/qset.c
> @@ -314,7 +314,7 @@ void qset_free_std(struct whc *whc, struct whc_std *std)
>  		kfree(std->bounce_buf);
>  	}
>  	if (std->pl_virt) {
> -		if (std->dma_addr)
> +		if (!dma_mapping_error(whc->wusbhc.dev, std->dma_addr))
>  			dma_unmap_single(whc->wusbhc.dev, std->dma_addr,
>  					 std->num_pointers * sizeof(struct whc_page_list_entry),
>  					 DMA_TO_DEVICE);
> @@ -535,9 +535,11 @@ static int qset_add_urb_sg(struct whc *whc, struct whc_qset *qset, struct urb *u
>  	list_for_each_entry(std, &qset->stds, list_node) {
>  		if (std->ntds_remaining == -1) {
>  			pl_len = std->num_pointers * sizeof(struct whc_page_list_entry);
> -			std->ntds_remaining = ntds--;
>  			std->dma_addr = dma_map_single(whc->wusbhc.dev, std->pl_virt,
>  						       pl_len, DMA_TO_DEVICE);
> +			if (dma_mapping_error(whc->wusbhc.dev, std->dma_addr))
> +				return -EFAULT;
> +			std->ntds_remaining = ntds--;
>  		}
>  	}
>  	return 0;
> @@ -618,6 +620,8 @@ static int qset_add_urb_sg_linearize(struct whc *whc, struct whc_qset *qset,
>  
>  		std->dma_addr = dma_map_single(&whc->umc->dev, std->bounce_buf, std->len,
>  					       is_out ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
> +		if (dma_mapping_error(&whc->umc->dev, std->dma_addr))
> +			return -EFAULT;

>From whc_probe() looks like &whc->umc->dev is the same as whc->wusbhc.dev,
so the change is correct, but I would suggest to unify the pointer to a device.

Still the driver has many problems, e.g. double kfree() -- error path
in qset_fill_page_list() and qset_free_stds() etc.

>  		if (qset_fill_page_list(whc, std, mem_flags) < 0)
>  			return -ENOMEM;
> 

--
With best wishes,
Vladimir