From ffbebe7649c32139e765e9c64838a7d0a28bbd24 Mon Sep 17 00:00:00 2001
From: Ryder Lee <ryder.lee@mediatek.com>
Date: Wed, 14 Jul 2021 17:18:48 +0800
Subject: [PATCH] mt76: mt7915: take RCU read lock when calling
 ieee80211_bss_get_elem()
Git-commit: ffbebe7649c32139e765e9c64838a7d0a28bbd24
References: git-fixes
Patch-mainline: v5.16-rc1

As ieee80211_bss_get_elem() derefences an RCU to return ie, both
the call to this function and any operation on this variable need
protection by the RCU read lock.

Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Oliver Neukum <oneukum@suse.com>
---
 drivers/net/wireless/mediatek/mt76/mt7915/mcu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
index bab652eae434..2ba3d92ebd70 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -923,12 +923,15 @@ static void mt7915_check_he_obss_narrow_bw_ru_iter(struct wiphy *wiphy,
 	struct mt7915_he_obss_narrow_bw_ru_data *data = _data;
 	const struct element *elem;
 
+	rcu_read_lock();
 	elem = ieee80211_bss_get_elem(bss, WLAN_EID_EXT_CAPABILITY);
 
 	if (!elem || elem->datalen <= 10 ||
 	    !(elem->data[10] &
 	      WLAN_EXT_CAPA10_OBSS_NARROW_BW_RU_TOLERANCE_SUPPORT))
 		data->tolerated = false;
+
+	rcu_read_unlock();
 }
 
 static bool mt7915_check_he_obss_narrow_bw_ru(struct ieee80211_hw *hw,
-- 
2.35.3