On Wed, 2020-11-18 at 09:53 +0800, 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@xxxxxxxxx>
This patchset looks good to me.
Thank you.
Acked-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
> ---
> drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> 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");
