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From:   Fabio Aiuto <fabioaiuto83@gmail.com>
To:     gregkh@linuxfoundation.org
Cc:     hdegoede@redhat.com, Larry.Finger@lwfinger.net,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
        Fabio Aiuto <fabioaiuto83@gmail.com>
Subject: [PATCH] staging: rtl8723bs: protect sleepq_len access by sleep_q.lock
Date:   Mon, 13 Sep 2021 15:03:46 +0200
Message-Id: <20210913130346.2390-1-fabioaiuto83@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

protect sleepq_len access by sleep_q.lock and move
pxmitpriv->lock after sleep_q.lock release.

This fixes and completes a lockdep warning silencing
done in a prevoius commit where accesses to sleep_q
related fields were protected by sleep_q.lock instead
of pxmitpriv->lock.

Note that sleep_q.lock is already taken inside
rtw_free_xmitframe_queue so we just wrap sleepq_len
access.

Moved pxmitpriv->lock after sleep_q.lock release to
avoid locks nesting.

Fixes: 78a1614a81f0 ("staging: rtl8723bs: remove possible deadlock when disconnect")
Reported-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Fabio Aiuto <fabioaiuto83@gmail.com>
Signed-off-by: Fabio Aiuto <fabioaiuto83@gmail.com>
---
 drivers/staging/rtl8723bs/core/rtw_sta_mgt.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c b/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c
index bf090f3b1db6..c98918e02afe 100644
--- a/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c
+++ b/drivers/staging/rtl8723bs/core/rtw_sta_mgt.c
@@ -294,10 +294,12 @@ u32 rtw_free_stainfo(struct adapter *padapter, struct sta_info *psta)
 
 	/* list_del_init(&psta->wakeup_list); */
 
-	spin_lock_bh(&pxmitpriv->lock);
-
 	rtw_free_xmitframe_queue(pxmitpriv, &psta->sleep_q);
+	spin_lock_bh(&psta->sleep_q.lock);
 	psta->sleepq_len = 0;
+	spin_unlock_bh(&psta->sleep_q.lock);
+
+	spin_lock_bh(&pxmitpriv->lock);
 
 	/* vo */
 	/* spin_lock_bh(&(pxmitpriv->vo_pending.lock)); */
-- 
2.20.1