wifi: ath11k: use work queue to process beacon tx event

Commit 3a415daa3e8b ("wifi: ath11k: add P2P IE in beacon template")
from Feb 28, 2024 (linux-next), leads to the following Smatch static
checker warning:

drivers/net/wireless/ath/ath11k/wmi.c:1742 ath11k_wmi_p2p_go_bcn_ie()
warn: sleeping in atomic context

The reason is that ath11k_bcn_tx_status_event() will directly call might
sleep function ath11k_wmi_cmd_send() during RCU read-side critical
sections. The call trace is like:

ath11k_bcn_tx_status_event()
-> rcu_read_lock()
-> ath11k_mac_bcn_tx_event()
	-> ath11k_mac_setup_bcn_tmpl()
	……
		-> ath11k_wmi_bcn_tmpl()
			-> ath11k_wmi_cmd_send()
-> rcu_read_unlock()

Commit 886433a98425 ("ath11k: add support for BSS color change") added the
ath11k_mac_bcn_tx_event(), commit 01e782c89108 ("ath11k: fix warning
of RCU usage for ath11k_mac_get_arvif_by_vdev_id()") added the RCU lock
to avoid warning but also introduced this BUG.

Use work queue to avoid directly calling ath11k_mac_bcn_tx_event()
during RCU critical sections. No need to worry about the deletion of vif
because cancel_work_sync() will drop the work if it doesn't start or
block vif deletion until the running work is done.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3.6510.30

Fixes: 3a415daa3e8b ("wifi: ath11k: add P2P IE in beacon template")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/2d277abd-5e7b-4da0-80e0-52bd96337f6e@moroto.mountain/
Signed-off-by: Kang Yang <quic_kangyang@quicinc.com>
Acked-by: Jeff Johnson <quic_jjohnson@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://patch.msgid.link/20240626053543.1946-1-quic_kangyang@quicinc.com

diff --git a/drivers/net/wireless/ath/ath11k/core.h b/drivers/net/wireless/ath/ath11k/core.h
index df24f0e409afb1b17345c14a29f5b7c24edd45c8..7122176dd91ea1643b1a1031a8d7a16385cba9b7 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/core.h
+++ b/drivers/net/wireless/ath/ath11k/core.h
@@ -399,6 +399,7 @@ struct ath11k_vif {
        u8 bssid[ETH_ALEN];
        struct cfg80211_bitrate_mask bitrate_mask;
        struct delayed_work connection_loss_work;
+       struct work_struct bcn_tx_work;
        int num_legacy_stations;
        int rtscts_prot_mode;
        int txpower;

diff --git a/drivers/net/wireless/ath/ath11k/mac.c b/drivers/net/wireless/ath/ath11k/mac.c
index ba910ae2c6769825316664e9407345baf5d64435..71ef89be823b924bb42213c2a96c2f9606a0812d 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/mac.c
+++ b/drivers/net/wireless/ath/ath11k/mac.c
@@ -6599,6 +6599,16 @@ static int ath11k_mac_vdev_delete(struct ath11k *ar, struct ath11k_vif *arvif)
        return ret;
 }
 
+static void ath11k_mac_bcn_tx_work(struct work_struct *work)
+{
+       struct ath11k_vif *arvif = container_of(work, struct ath11k_vif,
+                                               bcn_tx_work);
+
+       mutex_lock(&arvif->ar->conf_mutex);
+       ath11k_mac_bcn_tx_event(arvif);
+       mutex_unlock(&arvif->ar->conf_mutex);
+}
+
 static int ath11k_mac_op_add_interface(struct ieee80211_hw *hw,
                                       struct ieee80211_vif *vif)
 {
@@ -6637,6 +6647,7 @@ static int ath11k_mac_op_add_interface(struct ieee80211_hw *hw,
        arvif->vif = vif;
 
        INIT_LIST_HEAD(&arvif->list);
+       INIT_WORK(&arvif->bcn_tx_work, ath11k_mac_bcn_tx_work);
        INIT_DELAYED_WORK(&arvif->connection_loss_work,
                          ath11k_mac_vif_sta_connection_loss_work);
 
@@ -6879,6 +6890,7 @@ static void ath11k_mac_op_remove_interface(struct ieee80211_hw *hw,
        int i;
 
        cancel_delayed_work_sync(&arvif->connection_loss_work);
+       cancel_work_sync(&arvif->bcn_tx_work);
 
        mutex_lock(&ar->conf_mutex);
 

diff --git a/drivers/net/wireless/ath/ath11k/wmi.c b/drivers/net/wireless/ath/ath11k/wmi.c
index 38f175dd15578a312bce3d457aee1cd7b8acad51..2662092ee00a9c1963ce2aee0f5d47c605f4ac4c 100644 (file)
--- a/drivers/net/wireless/ath/ath11k/wmi.c
+++ b/drivers/net/wireless/ath/ath11k/wmi.c
@@ -7404,7 +7404,9 @@ static void ath11k_bcn_tx_status_event(struct ath11k_base *ab, struct sk_buff *s
                rcu_read_unlock();
                return;
        }
-       ath11k_mac_bcn_tx_event(arvif);
+
+       queue_work(ab->workqueue, &arvif->bcn_tx_work);
+
        rcu_read_unlock();
 }