From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [BUG] marvell: mwifiex: two possible ABBA deadlocks
To:     amitkarwar@gmail.com, ganapathi017@gmail.com,
        sharvari.harisangam@nxp.com, huxinming820@gmail.com,
        kvalo@codeaurora.org, David Miller <davem@davemloft.net>,
        kuba@kernel.org
Cc:     linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>
Message-ID: <0e495b14-efbb-e0da-37bd-af6bd677ee2c@gmail.com>
Date:   Tue, 23 Nov 2021 11:31:34 +0800
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Hello,

My static analysis tool reports two possible ABBA deadlocks in the 
mwifiex driver in Linux 5.10:

# DEADLOCK 1:
mwifiex_dequeue_tx_packet()
   spin_lock_bh(&priv->wmm.ra_list_spinlock); --> Line 1432 (Lock A)
   mwifiex_send_addba()
     spin_lock_bh(&priv->sta_list_spinlock); --> Line 608 (Lock B)

mwifiex_process_sta_tx_pause()
   spin_lock_bh(&priv->sta_list_spinlock); --> Line 398 (Lock B)
   mwifiex_update_ralist_tx_pause()
     spin_lock_bh(&priv->wmm.ra_list_spinlock); --> Line 941 (Lock A)

When mwifiex_dequeue_tx_packet() and mwifiex_process_sta_tx_pause() are 
concurrently executed, the deadlock can occur.

# DEADLOCK 2:
mwifiex_dequeue_tx_packet()
   spin_lock_bh(&priv->wmm.ra_list_spinlock); --> Line 1432 (Lock A)
   mwifiex_send_addba()
     spin_lock_bh(&priv->sta_list_spinlock); --> Line 608 (Lock B)

mwifiex_process_uap_tx_pause()
   spin_lock_bh(&priv->sta_list_spinlock); --> Line 363 (Lock B)
   mwifiex_update_ralist_tx_pause()
     spin_lock_bh(&priv->wmm.ra_list_spinlock); --> Line 941 (Lock A)

When mwifiex_dequeue_tx_packet() and mwifiex_process_uap_tx_pause() are 
concurrently executed, the deadlock can occur.

I am not quite sure whether these possible deadlocks are real and how to 
fix them if they are real.
Any feedback would be appreciated, thanks :)

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>


Best wishes,
Jia-Ju Bai