From f3d825a35920714fb7f73e4d4f36ea2328860660 Mon Sep 17 00:00:00 2001 From: Jiri Kosina Date: Tue, 15 Feb 2022 20:37:51 +0100 Subject: [PATCH] rtw89: fix RCU usage in rtw89_core_txq_push() 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: 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 ============================= 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: 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 Signed-off-by: Jiri Kosina Acked-by: Ping-Ke Shih Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/nycvar.YFH.7.76.2202152037000.11721@cbobk.fhfr.pm --- 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 63828dbfef4e..36b1dde007c7 100644 --- a/drivers/net/wireless/realtek/rtw89/core.c +++ b/drivers/net/wireless/realtek/rtw89/core.c @@ -1669,11 +1669,12 @@ 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); @@ -1683,6 +1684,8 @@ 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)