[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <d3996305-136a-708b-0dba-e9428f9da5cb@lwfinger.net>
Date: Wed, 18 Nov 2020 11:20:24 -0600
From: Larry Finger <Larry.Finger@...inger.net>
To: Jia-Ju Bai <baijiaju1990@...il.com>, pkshih@...ltek.com,
kvalo@...eaurora.org, davem@...emloft.net, kuba@...nel.org
Cc: linux-wireless@...r.kernel.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 1/4] rtlwifi: rtl8188ee: avoid accessing the data
mapped to streaming DMA
On 11/17/20 7:53 PM, Jia-Ju Bai wrote:
> In rtl88ee_tx_fill_cmddesc(), skb->data is mapped to streaming DMA on
> line 677:
> dma_addr_t mapping = dma_map_single(..., skb->data, ...);
>
> On line 680, skb->data is assigned to hdr after cast:
> struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)(skb->data);
>
> Then hdr->frame_control is accessed on line 681:
> __le16 fc = hdr->frame_control;
>
> This DMA access may cause data inconsistency between CPU and hardwre.
>
> To fix this bug, hdr->frame_control is accessed before the DMA mapping.
>
> Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
> ---
> drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
What changed between v1 and v2?
As outlined in Documentation/process/submitting-patches.rst, you should add a
'---' marker and descrive what was changed. I usually summarize the changes, but
it is also possible to provide a diffstat of the changes as the above file shows.
Larry
>
> diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c
> index b9775eec4c54..c948dafa0c80 100644
> --- a/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c
> +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c
> @@ -674,12 +674,12 @@ void rtl88ee_tx_fill_cmddesc(struct ieee80211_hw *hw,
> u8 fw_queue = QSLT_BEACON;
> __le32 *pdesc = (__le32 *)pdesc8;
>
> - dma_addr_t mapping = dma_map_single(&rtlpci->pdev->dev, skb->data,
> - skb->len, DMA_TO_DEVICE);
> -
> struct ieee80211_hdr *hdr = (struct ieee80211_hdr *)(skb->data);
> __le16 fc = hdr->frame_control;
>
> + dma_addr_t mapping = dma_map_single(&rtlpci->pdev->dev, skb->data,
> + skb->len, DMA_TO_DEVICE);
> +
> if (dma_mapping_error(&rtlpci->pdev->dev, mapping)) {
> rtl_dbg(rtlpriv, COMP_SEND, DBG_TRACE,
> "DMA mapping error\n");
>
Powered by blists - more mailing lists