In rtl8723e_tx_fill_cmddesc(), skb->data is mapped to streaming DMA on
line 531:
dma_addr_t mapping = dma_map_single(..., skb->data, ...);
On line 534, 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 535:
__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>
---
v2:
* Use "rtlwifi" as subject prefix and have all rtlwifi patches in the
same pathset.
Thank Ping and Larry for good advice.
---
drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.c b/drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.c
index e3ee91b7ea8d..340b3d68a54e 100644
--- a/drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.c
+++ b/drivers/net/wireless/realtek/rtlwifi/rtl8723ae/trx.c
@@ -528,12 +528,12 @@ void rtl8723e_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");
--
2.17.1
