ath11k: acquire ab->base_lock in unassign when finding the peer by addr

ath11k_peer_find_by_addr states via lockdep that ab->base_lock must be
held when calling that function in order to protect the list. All
callers except ath11k_mac_op_unassign_vif_chanctx have that lock
acquired when calling ath11k_peer_find_by_addr. That lock is also not
transitively held by a path towards ath11k_mac_op_unassign_vif_chanctx.
The solution is to acquire the lock when calling
ath11k_peer_find_by_addr inside ath11k_mac_op_unassign_vif_chanctx.

I am currently working on a static analyser to detect missing locks and
this was a reported case. I manually verified the report by looking at
the code, but I do not have real hardware so this is compile tested
only.

Fixes: 701e48a43e15 ("ath11k: add packet log support for QCA6390")
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220314215253.92658-1-dossche.niels@gmail.com

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index 7cf1ea2..62d9558 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -7133,6 +7133,7 @@ ath11k_mac_op_unassign_vif_chanctx(struct ieee80211_hw *hw,
        struct ath11k *ar = hw->priv;
        struct ath11k_base *ab = ar->ab;
        struct ath11k_vif *arvif = (void *)vif->drv_priv;
+       struct ath11k_peer *peer;
        int ret;
 
        mutex_lock(&ar->conf_mutex);
@@ -7144,9 +7145,13 @@ ath11k_mac_op_unassign_vif_chanctx(struct ieee80211_hw *hw,
        WARN_ON(!arvif->is_started);
 
        if (ab->hw_params.vdev_start_delay &&
-           arvif->vdev_type == WMI_VDEV_TYPE_MONITOR &&
-           ath11k_peer_find_by_addr(ab, ar->mac_addr))
-               ath11k_peer_delete(ar, arvif->vdev_id, ar->mac_addr);
+           arvif->vdev_type == WMI_VDEV_TYPE_MONITOR) {
+               spin_lock_bh(&ab->base_lock);
+               peer = ath11k_peer_find_by_addr(ab, ar->mac_addr);
+               spin_unlock_bh(&ab->base_lock);
+               if (peer)
+                       ath11k_peer_delete(ar, arvif->vdev_id, ar->mac_addr);
+       }
 
        if (arvif->vdev_type == WMI_VDEV_TYPE_MONITOR) {
                ret = ath11k_mac_monitor_stop(ar);