[PATCH v4 1/2] wifi: ath11k: move update channel list from update reg worker to reg notifier

[Kang Yang <quic_kangyang@xxxxxxxxxxx>]

From: Wen Gong <quic_wgong@xxxxxxxxxxx>

Currently when ath11k gets new channel list, it will mainly do two things
in ath11k_regd_update():
1. update channel list to cfg80211 by reg_work.
2. update cfg80211's channel list to firmware by
ath11k_reg_update_chan_list().

Flow:
ath11k_regd_update
->regulatory_set_wiphy_regd
        -> schedule_work(&reg_work)
                ->reg_work->reg_process_self_managed_hint
                        ->handle_band_custom(update to cfg80211)
-> ath11k_reg_update_chan_list(update to firmware)

But ath11k_reg_update_chan_list() is immediately called after reg_work
is queued. They are running in different threads. At this time,
ath11k_reg_update_chan_list() may use a wrong channel list because
handle_band_custom() may not be finished.
This may result in out-of-bounds write errors:
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

So should make sure ath11k_reg_update_chan_list() is called after
handle_band_custom() is finished.

reg_process_self_managed_hint() will call reg_call_notifier() after
handle_band_custom(). This function will call ath11k_reg_notifier(), so
move ath11k_reg_update_chan_list() to ath11k_reg_notifier(). Then
ath11k can update correct channel list to firmware.

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@xxxxxxxxxxx>
Signed-off-by: Kang Yang <quic_kangyang@xxxxxxxxxxx>
---
 drivers/net/wireless/ath/ath11k/reg.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/ath/ath11k/reg.c b/drivers/net/wireless/ath/ath11k/reg.c
index b0f289784dd3..cb2cf9b63d18 100644
--- a/drivers/net/wireless/ath/ath11k/reg.c
+++ b/drivers/net/wireless/ath/ath11k/reg.c
@@ -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