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@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20201119015218.12220-1-baijiaju1990@gmail.com
8b2c13b2e5