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Message-ID: <58fa5d4b7d794228ad45485ec5b979df@realtek.com>
Date: Wed, 16 Feb 2022 00:27:06 +0000
From: Pkshih <pkshih@...ltek.com>
To: Jiri Kosina <jkosina@...e.cz>, Kalle Valo <kvalo@...nel.org>
CC: Johannes Berg <johannes@...solutions.net>,
"linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] rtw89: fix RCU usage in rtw89_core_txq_push()
> -----Original Message-----
> From: Jiri Kosina <jkosina@...e.cz>
> Sent: Wednesday, February 16, 2022 3:38 AM
> To: Kalle Valo <kvalo@...nel.org>
> Cc: Johannes Berg <johannes@...solutions.net>; linux-wireless@...r.kernel.org;
> linux-kernel@...r.kernel.org; Pkshih <pkshih@...ltek.com>
> Subject: [PATCH] rtw89: fix RCU usage in rtw89_core_txq_push()
>
> From: Jiri Kosina <jkosina@...e.cz>
> 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:
> <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@...e.cz>
Acked-by: Ping-Ke Shih <pkshih@...ltek.com>
Thanks for your finding.
> ---
> 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 a0737eea9f81..9632e7f218dd 100644
> --- a/drivers/net/wireless/realtek/rtw89/core.c
> +++ b/drivers/net/wireless/realtek/rtw89/core.c
> @@ -1509,11 +1509,12 @@ 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);
> @@ -1523,6 +1524,8 @@ 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)
>
> --
> Jiri Kosina
> SUSE Labs
>
>
> ------Please consider the environment before printing this e-mail.
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