[PATCH v2 2/2] wifi: ath11k: fix dfs radar event locking

[Johan Hovold]

The ath11k active pdevs are protected by RCU but the DFS radar event
handling code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a
read-side critical section.

Mark the code in question as an RCU read-side critical section to avoid
any potential use-after-free issues.

Fixes: d5c65159f289 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Cc: stable@xxxxxxxxxxxxxxx      # 5.6
Acked-by: Jeff Johnson <quic_jjohnson@xxxxxxxxxxx>
Signed-off-by: Johan Hovold <johan+linaro@xxxxxxxxxx>
---
 drivers/net/wireless/ath/ath11k/wmi.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c
index da1582b8dc30..f0eac6cb84fd 100644
--- a/drivers/net/wireless/ath/ath11k/wmi.c
+++ b/drivers/net/wireless/ath/ath11k/wmi.c
@@ -8337,6 +8337,8 @@ ath11k_wmi_pdev_dfs_radar_detected_event(struct ath11k_base *ab, struct sk_buff
 		   ev->detector_id, ev->segment_id, ev->timestamp, ev->is_chirp,
 		   ev->freq_offset, ev->sidx);
 
+	rcu_read_lock();
+
 	ar = ath11k_mac_get_ar_by_pdev_id(ab, ev->pdev_id);
 
 	if (!ar) {
@@ -8354,6 +8356,8 @@ ath11k_wmi_pdev_dfs_radar_detected_event(struct ath11k_base *ab, struct sk_buff
 		ieee80211_radar_detected(ar->hw);
 
 exit:
+	rcu_read_unlock();
+
 	kfree(tb);
 }
 
-- 
2.41.0