[PATCH 5.16 064/285] rtw89: fix RCU usage in rtw89_core_txq_push()

Greg Kroah-Hartman
2022-04-12T07:49:59Z

From: Jiri Kosina <jkosina@suse.cz>

[ Upstream commit f3d825a35920714fb7f73e4d4f36ea2328860660 ]

ieee80211_tx_h_select_key() is performing a series of RCU dereferences,
but rtw89_core_txq_push() is calling it (via ieee80211_tx_dequeue_ni())
without RCU read-side lock held; fix that.

This addresses the splat below.

=============================
WARNING: suspicious RCU usage
5.17.0-rc4-00003-gccad664b7f14 #3 Tainted: G E
-----------------------------
net/mac80211/tx.c:593 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/u33:0/184:
#0: ffff9c0b14811d38 ((wq_completion)rtw89_tx_wq){+.+.}-{0:0}, at: process_one_work+0x258/0x660
#1: ffffb97380cf3e78 ((work_completion)(&rtwdev->txq_work)){+.+.}-{0:0}, at: process_one_work+0x258/0x660

stack backtrace:
CPU: 8 PID: 184 Comm: kworker/u33:0 Tainted: G E 5.17.0-rc4-00003-gccad664b7f14 #3 473b49ab0e7c2d6af2900c756bfd04efd7a9de13
Hardware name: LENOVO 20UJS2B905/20UJS2B905, BIOS R1CET63W(1.32 ) 04/09/2021
Workqueue: rtw89_tx_wq rtw89_core_txq_work [rtw89_core]
Call Trace:
<TASK>
dump_stack_lvl+0x58/0x71
ieee80211_tx_h_select_key+0x2c0/0x530 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
ieee80211_tx_dequeue+0x1a7/0x1260 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
rtw89_core_txq_work+0x1a6/0x420 [rtw89_core b39ba493f2e517ad75e0f8187ecc24edf58bbbea]
process_one_work+0x2d8/0x660
worker_thread+0x39/0x3e0
? process_one_work+0x660/0x660
kthread+0xe5/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>

=============================
WARNING: suspicious RCU usage
5.17.0-rc4-00003-gccad664b7f14 #3 Tainted: G E
-----------------------------
net/mac80211/tx.c:607 suspicious rcu_dereference_check() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
2 locks held by kworker/u33:0/184:
#0: ffff9c0b14811d38 ((wq_completion)rtw89_tx_wq){+.+.}-{0:0}, at: process_one_work+0x258/0x660
#1: ffffb97380cf3e78 ((work_completion)(&rtwdev->txq_work)){+.+.}-{0:0}, at: process_one_work+0x258/0x660

stack backtrace:
CPU: 8 PID: 184 Comm: kworker/u33:0 Tainted: G E 5.17.0-rc4-00003-gccad664b7f14 #3 473b49ab0e7c2d6af2900c756bfd04efd7a9de13
Hardware name: LENOVO 20UJS2B905/20UJS2B905, BIOS R1CET63W(1.32 ) 04/09/2021
Workqueue: rtw89_tx_wq rtw89_core_txq_work [rtw89_core]
Call Trace:
<TASK>
dump_stack_lvl+0x58/0x71
ieee80211_tx_h_select_key+0x464/0x530 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
ieee80211_tx_dequeue+0x1a7/0x1260 [mac80211 911c23e2351c0ae60b597a67b1204a5ea955e365]
rtw89_core_txq_work+0x1a6/0x420 [rtw89_core b39ba493f2e517ad75e0f8187ecc24edf58bbbea]
process_one_work+0x2d8/0x660
worker_thread+0x39/0x3e0
? process_one_work+0x660/0x660
kthread+0xe5/0x110
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x22/0x30
</TASK>

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/nycvar.YFH.7.76.2202152037000.11721@cbobk.fhfr.pm
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/realtek/rtw89/core.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw89/core.c b/drivers/net/wireless/realtek/rtw89/core.c
index d02ec5a735cb..9d9c0984903f 100644
--- a/drivers/net/wireless/realtek/rtw89/core.c
+++ b/drivers/net/wireless/realtek/rtw89/core.c
@@ -1501,11 +1501,12 @@ static void rtw89_core_txq_push(struct rtw89_dev *rtwdev,
unsigned long i;
int ret;

+ rcu_read_lock();
for (i = 0; i < frame_cnt; i++) {
skb = ieee80211_tx_dequeue_ni(rtwdev->hw, txq);
if (!skb) {
rtw89_debug(rtwdev, RTW89_DBG_TXRX, "dequeue a NULL skb\n");
- return;
+ goto out;
}
rtw89_core_txq_check_agg(rtwdev, rtwtxq, skb);
ret = rtw89_core_tx_write(rtwdev, vif, sta, skb, NULL);
@@ -1515,6 +1516,8 @@ static void rtw89_core_txq_push(struct rtw89_dev *rtwdev,
break;
}
}
+out:
+ rcu_read_unlock();
}

static u32 rtw89_check_and_reclaim_tx_resource(struct rtw89_dev *rtwdev, u8 tid)
--
2.35.1