[PATCH v5 1/2] wifi: ath11k: update channel list in reg notifier instead reg worker

[Kang Yang]

From: Wen Gong <quic_wgong at quicinc.com>

Currently when ath11k gets a new channel list, it will be processed
according to the following steps:
1. update new channel list to cfg80211 and queue reg_work.
2. cfg80211 handles new channel list during reg_work.
3. update cfg80211's handled channel list to firmware by
ath11k_reg_update_chan_list().

But ath11k will immediately execute step 3 after reg_work is just
queued. Since step 2 is asynchronous, cfg80211 may not have completed
handling the new channel list, which may leading to an out-of-bounds
write error:
BUG: KASAN: slab-out-of-bounds in ath11k_reg_update_chan_list
Call Trace:
    ath11k_reg_update_chan_list+0xbfe/0xfe0 [ath11k]
    kfree+0x109/0x3a0
    ath11k_regd_update+0x1cf/0x350 [ath11k]
    ath11k_regd_update_work+0x14/0x20 [ath11k]
    process_one_work+0xe35/0x14c0

Should ensure step 2 is completely done before executing step 3. Thus
Wen raised patch[1]. When flag NL80211_REGDOM_SET_BY_DRIVER is set,
cfg80211 will notify ath11k after step 2 is done.

So enable the flag NL80211_REGDOM_SET_BY_DRIVER then cfg80211 will
notify ath11k after step 2 is done. At this time, there will be no
KASAN bug during the execution of the step 3.

[1] https://patchwork.kernel.org/project/linux-wireless/patch/20230201065313.27203-1-quic_wgong@quicinc.com/

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03125-QCAHSPSWPL_V1_V2_SILICONZ_LITE-3

Fixes: f45cb6b29cd3 ("wifi: ath11k: avoid deadlock during regulatory update in ath11k_regd_update()")
Signed-off-by: Wen Gong <quic_wgong at quicinc.com>
Signed-off-by: Kang Yang <quic_kangyang at quicinc.com>
---
 drivers/net/wireless/ath/ath11k/reg.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/reg.c b/drivers/net/wireless/ath/ath11k/reg.c
index b0f289784dd3..7bfe47ad62a0 100644
--- a/drivers/net/wireless/ath/ath11k/reg.c
+++ b/drivers/net/wireless/ath/ath11k/reg.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: BSD-3-Clause-Clear
 /*
  * Copyright (c) 2018-2019 The Linux Foundation. All rights reserved.
- * Copyright (c) 2021-2024 Qualcomm Innovation Center, Inc. All rights reserved.
+ * Copyright (c) 2021-2025 Qualcomm Innovation Center, Inc. All rights reserved.
  */
 #include <linux/rtnetlink.h>
 
@@ -55,6 +55,19 @@ ath11k_reg_notifier(struct wiphy *wiphy, struct regulatory_request *request)
 	ath11k_dbg(ar->ab, ATH11K_DBG_REG,
 		   "Regulatory Notification received for %s\n", wiphy_name(wiphy));
 
+	if (request->initiator == NL80211_REGDOM_SET_BY_DRIVER) {
+		ath11k_dbg(ar->ab, ATH11K_DBG_REG,
+			   "driver initiated regd update\n");
+		if (ar->state != ATH11K_STATE_ON)
+			return;
+
+		ret = ath11k_reg_update_chan_list(ar, true);
+		if (ret)
+			ath11k_warn(ar->ab, "failed to update channel list: %d\n", ret);
+
+		return;
+	}
+
 	/* Currently supporting only General User Hints. Cell base user
 	 * hints to be handled later.
 	 * Hints from other sources like Core, Beacons are not expected for
@@ -293,12 +306,6 @@ int ath11k_regd_update(struct ath11k *ar)
 	if (ret)
 		goto err;
 
-	if (ar->state == ATH11K_STATE_ON) {
-		ret = ath11k_reg_update_chan_list(ar, true);
-		if (ret)
-			goto err;
-	}
-
 	return 0;
 err:
 	ath11k_warn(ab, "failed to perform regd update : %d\n", ret);
@@ -977,6 +984,7 @@ void ath11k_regd_update_work(struct work_struct *work)
 void ath11k_reg_init(struct ath11k *ar)
 {
 	ar->hw->wiphy->regulatory_flags = REGULATORY_WIPHY_SELF_MANAGED;
+	ar->hw->wiphy->flags |= WIPHY_FLAG_NOTIFY_REGDOM_BY_DRIVER;
 	ar->hw->wiphy->reg_notifier = ath11k_reg_notifier;
 }
 
-- 
2.34.1