wifi: ath12k: Avoid accessing uninitialized arvif->ar during beacon miss

During beacon miss handling, ath12k driver iterates over active virtual
interfaces (vifs) and attempts to access the radio object (ar) via
arvif->deflink->ar.

However, after commit aa80f12 ("wifi: ath12k: defer vdev creation for
MLO"), arvif is linked to a radio only after vdev creation, typically when
a channel is assigned or a scan is requested.
For P2P capable devices, a default P2P interface is created by
wpa_supplicant along with regular station interfaces, these serve as dummy
interfaces for P2P-capable stations, lack an associated netdev and initiate
frequent scans to discover neighbor p2p devices. When a scan is initiated
on such P2P vifs, driver selects destination radio (ar) based on scan
frequency, creates a scan vdev, and attaches arvif to the radio. Once the
scan completes or is aborted, the scan vdev is deleted, detaching arvif
from the radio and leaving arvif->ar uninitialized.

While handling beacon miss for station interfaces, P2P interface is also
encountered in the vif iteration and ath12k_mac_handle_beacon_miss_iter()
tries to dereference the uninitialized arvif->deflink->ar.

Fix this by verifying that vdev is created for the arvif before accessing
its ar during beacon miss handling and similar vif iterator callbacks.

==========================================================================
 wlp6s0: detected beacon loss from AP (missed 7 beacons) - probing
 KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017]

 CPU: 5 UID: 0 PID: 0 Comm: swapper/5 Not tainted 6.16.0-rc1-wt-ath+ #2 PREEMPT(full)
 RIP: 0010:ath12k_mac_handle_beacon_miss_iter+0xb5/0x1a0 [ath12k]
 Call Trace:
  __iterate_interfaces+0x11a/0x410 [mac80211]
  ieee80211_iterate_active_interfaces_atomic+0x61/0x140 [mac80211]
  ath12k_mac_handle_beacon_miss+0xa1/0xf0 [ath12k]
  ath12k_roam_event+0x393/0x560 [ath12k]
  ath12k_wmi_op_rx+0x1486/0x28c0 [ath12k]
  ath12k_htc_process_trailer.isra.0+0x2fb/0x620 [ath12k]
  ath12k_htc_rx_completion_handler+0x448/0x830 [ath12k]
  ath12k_ce_recv_process_cb+0x549/0x9e0 [ath12k]
  ath12k_ce_per_engine_service+0xbe/0xf0 [ath12k]
  ath12k_pci_ce_workqueue+0x69/0x120 [ath12k]
  process_one_work+0xe3a/0x1430

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.4.1-00199-QCAHKSWPL_SILICONZ-1
Tested-on: WCN7850 hw2.0 PCI WLAN.HMT.1.1.c5-00284.1-QCAHMTSWPL_V1.0_V2.0_SILICONZ-3

Fixes: aa80f12 ("wifi: ath12k: defer vdev creation for MLO")
Signed-off-by: Rameshkumar Sundaram <rameshkumar.sundaram@oss.qualcomm.com>
Reviewed-by: Vasanthakumar Thiagarajan <vasanthakumar.thiagarajan@oss.qualcomm.com>
Link: https://patch.msgid.link/20250618185635.750470-1-rameshkumar.sundaram@oss.qualcomm.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>

Author: Rameshkumar Sundaram

drivers/net/wireless/ath/ath12k/mac.c

@@ -693,6 +693,9 @@ static void ath12k_get_arvif_iter(void *data, u8 *mac,
 		if (WARN_ON(!arvif))
 			continue;
 
+		if (!arvif->is_created)
+			continue;
+
 		if (arvif->vdev_id == arvif_iter->vdev_id &&
 		    arvif->ar == arvif_iter->ar) {
 			arvif_iter->arvif = arvif;
@@ -1755,7 +1758,7 @@ static void ath12k_mac_handle_beacon_iter(void *data, u8 *mac,
 	struct ath12k_vif *ahvif = ath12k_vif_to_ahvif(vif);
 	struct ath12k_link_vif *arvif = &ahvif->deflink;
 
-	if (vif->type != NL80211_IFTYPE_STATION)
+	if (vif->type != NL80211_IFTYPE_STATION || !arvif->is_created)
 		return;
 
 	if (!ether_addr_equal(mgmt->bssid, vif->bss_conf.bssid))
@@ -1778,16 +1781,16 @@ static void ath12k_mac_handle_beacon_miss_iter(void *data, u8 *mac,
 	u32 *vdev_id = data;
 	struct ath12k_vif *ahvif = ath12k_vif_to_ahvif(vif);
 	struct ath12k_link_vif *arvif = &ahvif->deflink;
-	struct ath12k *ar = arvif->ar;
-	struct ieee80211_hw *hw = ath12k_ar_to_hw(ar);
+	struct ieee80211_hw *hw;
 
-	if (arvif->vdev_id != *vdev_id)
+	if (!arvif->is_created || arvif->vdev_id != *vdev_id)
 		return;
 
 	if (!arvif->is_up)
 		return;
 
 	ieee80211_beacon_loss(vif);
+	hw = ath12k_ar_to_hw(arvif->ar);
 
 	/* Firmware doesn't report beacon loss events repeatedly. If AP probe
 	 * (done by mac80211) succeeds but beacons do not resume then it
@@ -9818,7 +9821,7 @@ ath12k_mac_change_chanctx_cnt_iter(void *data, u8 *mac,
 		if (WARN_ON(!arvif))
 			continue;
 
-		if (arvif->ar != arg->ar)
+		if (!arvif->is_created || arvif->ar != arg->ar)
 			continue;
 
 		link_conf = wiphy_dereference(ahvif->ah->hw->wiphy,
@@ -9853,7 +9856,7 @@ ath12k_mac_change_chanctx_fill_iter(void *data, u8 *mac,
 		if (WARN_ON(!arvif))
 			continue;
 
-		if (arvif->ar != arg->ar)
+		if (!arvif->is_created || arvif->ar != arg->ar)
 			continue;
 
 		link_conf = wiphy_dereference(ahvif->ah->hw->wiphy,

drivers/net/wireless/ath/ath12k/p2p.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause-Clear
 /*
  * Copyright (c) 2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
  */
 
 #include <net/mac80211.h>
@@ -124,7 +125,7 @@ static void ath12k_p2p_noa_update_vdev_iter(void *data, u8 *mac,
 
 	WARN_ON(!rcu_read_lock_any_held());
 	arvif = &ahvif->deflink;
-	if (arvif->ar != arg->ar || arvif->vdev_id != arg->vdev_id)
+	if (!arvif->is_created || arvif->ar != arg->ar || arvif->vdev_id != arg->vdev_id)
 		return;
 
 	ath12k_p2p_noa_update(arvif, arg->noa);