wifi: ath12k: Pass ab pointer directly to ath12k_dp_tx_get_encap_type()
In the Linux kernel, the following vulnerability has been resolved:
wifi: ath12k: Pass ab pointer directly to ath12k_dp_tx_get_encap_type()
In ath12k_dp_tx_get_encap_type(), the arvif parameter is only used to retrieve the ab pointer. In vdev delete sequence the arvif->ar could become NULL and that would trigger kernel panic. Since the caller ath12k_dp_tx() already has a valid ab pointer, pass it directly to avoid panic and unnecessary dereferencing.
PC points to "ath12k_dp_tx+0x228/0x988 [ath12k]" LR points to "ath12k_dp_tx+0xc8/0x988 [ath12k]". The Backtrace obtained is as follows: ath12k_dp_tx+0x228/0x988 [ath12k] ath12k_mac_tx_check_max_limit+0x608/0x920 [ath12k] ieee80211_process_measurement_req+0x320/0x348 [mac80211] ieee80211_tx_dequeue+0x9ac/0x1518 [mac80211] ieee80211_tx_dequeue+0xb14/0x1518 [mac80211] ieee80211_tx_prepare_skb+0x224/0x254 [mac80211] ieee80211_xmit+0xec/0x100 [mac80211] __ieee80211_subif_start_xmit+0xc50/0xf40 [mac80211] ieee80211_subif_start_xmit+0x2e8/0x308 [mac80211] netdev_start_xmit+0x150/0x18c dev_hard_start_xmit+0x74/0xc0
Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.3.1-00173-QCAHKSWPL_SILICONZ-1