From: Lorenzo Bianconi lorenzo@kernel.org
[ 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@kernel.org Signed-off-by: Felix Fietkau nbd@nbd.name Signed-off-by: Sasha Levin sashal@kernel.org --- 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