| Message ID | 20201118015314.4979-1-baijiaju1990@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [v2,1/4] rtlwifi: rtl8188ee: avoid accessing the data mapped to streaming DMA | expand |
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 <baijiaju1990@gmail.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. >
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");
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@gmail.com> --- drivers/net/wireless/realtek/rtlwifi/rtl8188ee/trx.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)