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 <[email protected]>
> ---
> 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");
>
Thanks for the advice.
I have added the description of the changes and resent the patches.
Best wishes,
Jia-Ju Bai
On 2020/11/19 1:20, Larry Finger wrote:
> 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 <[email protected]>
>> ---
>> 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.
>