[PATCH] wifi: ath12k: Fix firmware stats leak on get_txpower error paths

[Saikiran]

The commits bd6ec8111e65 and 2977567b244f changed firmware stats handling
to be caller-driven, requiring explicit ath12k_fw_stats_reset() calls
after using ath12k_mac_get_fw_stats().

However, in ath12k_mac_op_get_txpower(), when ath12k_mac_get_fw_stats()
succeeds but the pdev stats list is empty, or when the stats request
fails, the function exits via err_fallback without resetting the stats
buffer.

This causes the stats buffer to accumulate data, eventually leading to
firmware communication failures (error -71/EPROTO) during subsequent
operations, particularly during 5GHz scanning which requires additional
TX power queries.

Symptoms:
- "failed to pull fw stats: -71" errors in dmesg  - 5GHz networks not detected despite hardware support
- 2.4GHz networks work normally

Fix this by calling ath12k_fw_stats_reset() on all error paths after
ath12k_mac_get_fw_stats() is called, ensuring the stats buffer is
always freed regardless of the execution path.

Fixes: bd6ec8111e65 ("wifi: ath12k: Make firmware stats reset caller-driven")
Link: https://bugs.launchpad.net/ubuntu-concept/+bug/2138308
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302 (Lenovo Yoga Slim 7x)

Signed-off-by: Saikiran <bjsaikiran at gmail.com>
---
 drivers/net/wireless/ath/ath12k/mac.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index f7a2a544bef2..4195364cb6e3 100644
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -5161,6 +5161,7 @@ static int ath12k_mac_op_get_txpower(struct ieee80211_hw *hw,
 	ret = ath12k_mac_get_fw_stats(ar, &params);
 	if (ret) {
 		ath12k_warn(ab, "failed to request fw pdev stats: %d\n", ret);
+		ath12k_fw_stats_reset(ar);
 		goto err_fallback;
 	}
 
@@ -5169,6 +5170,7 @@ static int ath12k_mac_op_get_txpower(struct ieee80211_hw *hw,
 					struct ath12k_fw_stats_pdev, list);
 	if (!pdev) {
 		spin_unlock_bh(&ar->data_lock);
+		ath12k_fw_stats_reset(ar);
 		goto err_fallback;
 	}
 
-- 
2.51.0