From: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
[ Upstream commit 481fc927c8289919cc0be58666fcd1b7da187a0c ]
Introduce rcu section in mt7921_mcu_tx_rate_report before dereferencing
wcid pointer otherwise loockdep will report the following issue:
[ 115.245740] =============================
[ 115.245754] WARNING: suspicious RCU usage
[ 115.245771] 5.10.20 #0 Not tainted
[ 115.245784] -----------------------------
[ 115.245816] other info that might help us debug this:
[ 115.245830] rcu_scheduler_active = 2, debug_locks = 1
[ 115.245845] 3 locks held by kworker/u4:1/20:
[ 115.245858] #0: ffffff80065ab138 ((wq_completion)phy0){+.+.}-{0:0}, at: process_one_work+0x1f8/0x6b8
[ 115.245948] #1: ffffffc01198bdd8 ((work_completion)(&(&dev->mphy.mac_work)->work)){+.+.}-{0:0}, at: process_one_8
[ 115.246027] #2: ffffff8006543ce8 (&dev->mutex#2){+.+.}-{3:3}, at: mt7921_mac_work+0x60/0x2b0 [mt7921e]
[ 115.246125]
[ 115.246125] stack backtrace:
[ 115.246142] CPU: 1 PID: 20 Comm: kworker/u4:1 Not tainted 5.10.20 #0
[ 115.246152] Hardware name: MediaTek MT7622 RFB1 board (DT)
[ 115.246168] Workqueue: phy0 mt7921_mac_work [mt7921e]
[ 115.246188] Call trace:
[ 115.246201] dump_backtrace+0x0/0x1a8
[ 115.246213] show_stack+0x14/0x30
[ 115.246228] dump_stack+0xec/0x134
[ 115.246240] lockdep_rcu_suspicious+0xcc/0xdc
[ 115.246255] mt7921_get_wtbl_info+0x2a4/0x310 [mt7921e]
[ 115.246269] mt7921_mac_work+0x284/0x2b0 [mt7921e]
[ 115.246281] process_one_work+0x2a0/0x6b8
[ 115.246293] worker_thread+0x40/0x440
[ 115.246305] kthread+0x144/0x148
[ 115.246317] ret_from_fork+0x10/0x18
Fixes: 1c099ab44727c ("mt76: mt7921: add MCU support")
Signed-off-by: Lorenzo Bianconi <lorenzo@xxxxxxxxxx>
Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/wireless/mediatek/mt76/mt7921/mcu.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
index 62afbad77596..9a140e4734b5 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/mcu.c
@@ -404,9 +404,12 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb,
if (wlan_idx >= MT76_N_WCIDS)
return;
+
+ rcu_read_lock();
+
wcid = rcu_dereference(dev->mt76.wcid[wlan_idx]);
if (!wcid)
- return;
+ goto out;
msta = container_of(wcid, struct mt7921_sta, wcid);
stats = &msta->stats;
@@ -414,6 +417,8 @@ mt7921_mcu_tx_rate_report(struct mt7921_dev *dev, struct sk_buff *skb,
/* current rate */
mt7921_mcu_tx_rate_parse(mphy, &peer, &rate, curr);
stats->tx_rate = rate;
+out:
+ rcu_read_unlock();
}
static void
--
2.30.2
