[PATCH v2 2/2] wifi: ath12k: Fix firmware stats leak when pdev list is empty

[Baochen Qiang]

On 1/26/2026 5:52 PM, Saikiran wrote:
> 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().
> 
> In ath12k_mac_op_get_txpower(), when ath12k_mac_get_fw_stats() succeeds
> but the pdev stats list is empty, the function exits without calling
> ath12k_fw_stats_reset(). Even though the pdev list is empty, the firmware
> may have populated other stats lists (vdevs, beacons, etc.) in the

'may' is not enough, we need to be 100% sure whether other stats are populated. This is
critical for us to find the root cause.

> ar->fw_stats structure.
> 
> Without resetting the stats buffer, this data accumulates across multiple
> calls, eventually causing the stats buffer to overflow and leading to
> firmware communication failures (error -71/EPROTO) during subsequent
> operations.
> 
> The issue manifests during 5GHz scanning which triggers multiple TX power
> queries. Symptoms include:
> - "failed to pull fw stats: -71" errors in dmesg

still, can you please check the logs to see at which exact place is this printed?

> - 5GHz networks not detected despite hardware support
> - 2.4GHz networks work normally
> 
> Fix by calling ath12k_fw_stats_reset() when the pdev list is empty,
> ensuring the stats buffer is properly cleaned up even when only partial
> stats data is received from firmware.
> 
> 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 | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
> index e0e49f782bf8..6e35c3ee9864 100644
> --- a/drivers/net/wireless/ath/ath12k/mac.c
> +++ b/drivers/net/wireless/ath/ath12k/mac.c
> @@ -5169,6 +5169,7 @@ 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;
>  	}
>