wifi: ath12k: use lockdep_assert_in_rcu_read_lock() for RCU assertions

Two functions in ath12k assert that the caller holds an RCU read lock:
ath12k_mac_get_arvif() and ath12k_p2p_noa_update_vdev_iter(). Both use:

    WARN_ON(!rcu_read_lock_any_held());

On kernels using preemptible RCU (CONFIG_PREEMPT=y or CONFIG_PREEMPT_RT=y)
without CONFIG_DEBUG_LOCK_ALLOC, this produces a false positive splat
whenever these functions are invoked from paths that do hold the RCU
read lock (e.g. firmware stats processing or mac80211 interface
iteration).

Root cause:

  - Without CONFIG_DEBUG_LOCK_ALLOC, rcu_read_lock_any_held() is a
    static inline that returns !preemptible() as a proxy for "in an
    RCU read section".

  - With preemptible RCU, rcu_read_lock() does not disable preemption.
    A task can therefore be preemptible while legitimately holding an
    RCU read lock, making the proxy unreliable.

  - Callers such as ath12k_wmi_tlv_rssi_chain_parse() (via guard(rcu)())
    and ieee80211_iterate_active_interfaces_atomic() do hold the RCU
    read lock, so these warnings are incorrect.

Typical splat seen on a WCN7850 station with periodic fw stats
processing:

  WARNING: drivers/net/wireless/ath/ath12k/mac.c:791 at
    ath12k_mac_get_arvif+0x9e/0xd0 [ath12k]
  Tainted: G W O 6.19.13-rt #1 PREEMPT_RT
  Call Trace:
   ath12k_wmi_tlv_rssi_chain_parse+0x69/0x170 [ath12k]
   ath12k_wmi_tlv_iter+0x7f/0x120 [ath12k]
   ath12k_wmi_tlv_fw_stats_parse+0x342/0x6b0 [ath12k]
   ath12k_wmi_op_rx+0xe9e/0x3150 [ath12k]
   ath12k_htc_rx_completion_handler+0x3df/0x5b0 [ath12k]
   ath12k_ce_per_engine_service+0x325/0x3e0 [ath12k]
   ath12k_pci_ce_workqueue+0x20/0x40 [ath12k]

Replace WARN_ON(!rcu_read_lock_any_held()) with
lockdep_assert_in_rcu_read_lock(), which is gated on CONFIG_PROVE_RCU
and therefore compiles out entirely when PROVE_RCU is disabled.
PROVE_RCU kernels continue to get the full lockdep-based check, and
the new helper precisely checks for rcu_read_lock() rather than any
RCU variant, which better matches the callers' expectations.

Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00302-QCAHMTSWPL_V1.0_V2.0_SILICONZ-1.115823.3

Fixes: 3dd2c68f206e ("wifi: ath12k: prepare vif data structure for MLO handling")
Suggested-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Suggested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com>
Reviewed-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Signed-off-by: Yu-Hsiang Tseng <asas1asas200@gmail.com>
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20260422180814.1938317-1-asas1asas200@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>

diff --git a/drivers/net/wireless/ath/ath12k/mac.c b/drivers/net/wireless/ath/ath12k/mac.c
index fbdfe6424fd7c2fd81ed2e8ad31ba86076868f46..df2334f3bad645ed86c8b2e20e06b35e284ab9c9 100644 (file)
--- a/drivers/net/wireless/ath/ath12k/mac.c
+++ b/drivers/net/wireless/ath/ath12k/mac.c
@@ -788,7 +788,7 @@ struct ath12k_link_vif *ath12k_mac_get_arvif(struct ath12k *ar, u32 vdev_id)
 
        /* To use the arvif returned, caller must have held rcu read lock.
         */
-       WARN_ON(!rcu_read_lock_any_held());
+       lockdep_assert_in_rcu_read_lock();
        arvif_iter.vdev_id = vdev_id;
        arvif_iter.ar = ar;
 

diff --git a/drivers/net/wireless/ath/ath12k/p2p.c b/drivers/net/wireless/ath/ath12k/p2p.c
index 59589748f1a8c2990da85b6a86e53e8f42e3d3d4..19ebcd1d8eb256ca62946ac9796a9a5594fbf07d 100644 (file)
--- a/drivers/net/wireless/ath/ath12k/p2p.c
+++ b/drivers/net/wireless/ath/ath12k/p2p.c
@@ -123,7 +123,7 @@ static void ath12k_p2p_noa_update_vdev_iter(void *data, u8 *mac,
        struct ath12k_p2p_noa_arg *arg = data;
        struct ath12k_link_vif *arvif;
 
-       WARN_ON(!rcu_read_lock_any_held());
+       lockdep_assert_in_rcu_read_lock();
        arvif = &ahvif->deflink;
        if (!arvif->is_created || arvif->ar != arg->ar || arvif->vdev_id != arg->vdev_id)
                return;