The ath12k active pdevs are protected by RCU but the DFS-radar and
temperature event handling code calling ath12k_mac_get_ar_by_pdev_id()
was not marked as a read-side critical section.

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

Note that the temperature event handler looks like a place holder
currently but would still trigger an RCU lockdep splat.

Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
Cc: stable@vger.kernel.org	# v6.2
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 drivers/net/wireless/ath/ath12k/wmi.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
index ef0f3cf35cfd..1a1f57c7ac7e 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.c
+++ b/drivers/net/wireless/ath/ath12k/wmi.c
@@ -6476,6 +6476,7 @@ ath12k_wmi_pdev_dfs_radar_detected_event(struct ath12k_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 = ath12k_mac_get_ar_by_pdev_id(ab, le32_to_cpu(ev->pdev_id));
 
 	if (!ar) {
@@ -6493,6 +6494,8 @@ ath12k_wmi_pdev_dfs_radar_detected_event(struct ath12k_base *ab, struct sk_buff
 		ieee80211_radar_detected(ar->hw);
 
 exit:
+	rcu_read_unlock();
+
 	kfree(tb);
 }
 
@@ -6511,11 +6514,14 @@ ath12k_wmi_pdev_temperature_event(struct ath12k_base *ab,
 	ath12k_dbg(ab, ATH12K_DBG_WMI,
 		   "pdev temperature ev temp %d pdev_id %d\n", ev.temp, ev.pdev_id);
 
+	rcu_read_lock();
 	ar = ath12k_mac_get_ar_by_pdev_id(ab, le32_to_cpu(ev.pdev_id));
 	if (!ar) {
 		ath12k_warn(ab, "invalid pdev id in pdev temperature ev %d", ev.pdev_id);
-		return;
+		goto exit;
 	}
+exit:
+	rcu_read_unlock();
 }
 
 static void ath12k_fils_discovery_event(struct ath12k_base *ab,
-- 
2.41.0

Johan Hovold <johan+linaro@kernel.org> wrote:

> The ath12k active pdevs are protected by RCU but the DFS-radar and
> temperature event handling code calling ath12k_mac_get_ar_by_pdev_id()
> was not marked as a read-side critical section.
> 
> Mark the code in question as RCU read-side critical sections to avoid
> any potential use-after-free issues.
> 
> Note that the temperature event handler looks like a place holder
> currently but would still trigger an RCU lockdep splat.
> 
> Compile tested only.
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Cc: stable@vger.kernel.org      # v6.2
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
> Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
> Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>

2 patches applied to ath-next branch of ath.git, thanks.

69bd216e0493 wifi: ath12k: fix dfs-radar and temperature event locking
6afc57ea315e wifi: ath12k: fix htt mlo-offset event locking

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20231019113650.9060-2-johan+linaro@kernel.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

On 10/19/2023 4:36 AM, Johan Hovold wrote:
> The ath12k active pdevs are protected by RCU but the DFS-radar and
> temperature event handling code calling ath12k_mac_get_ar_by_pdev_id()
> was not marked as a read-side critical section.
> 
> Mark the code in question as RCU read-side critical sections to avoid
> any potential use-after-free issues.
> 
> Note that the temperature event handler looks like a place holder
> currently but would still trigger an RCU lockdep splat.
> 
> Fixes: d889913205cf ("wifi: ath12k: driver for Qualcomm Wi-Fi 7 devices")
> Cc: stable@vger.kernel.org	# v6.2
> Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>