From: Brian Norris briannorris@chromium.org
[ Upstream commit 1b8bb8919ef81bfc8873d223b9361f1685f2106d ]
Quoting Jia-Ju Bai baijiaju1990@gmail.com:
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)
Similar report for mwifiex_process_uap_tx_pause().
While the locking expectations in this driver are a bit unclear, the Fixed commit only intended to protect the sta_ptr, so we can drop the lock as soon as we're done with it.
IIUC, this deadlock cannot actually happen, because command event processing (which calls mwifiex_process_sta_tx_pause()) is sequentialized with TX packet processing (e.g., mwifiex_dequeue_tx_packet()) via the main loop (mwifiex_main_process()). But it's good not to leave this potential issue lurking.
Fixes: f0f7c2275fb9 ("mwifiex: minor cleanups w/ sta_list_spinlock in cfg80211.c") Cc: Douglas Anderson dianders@chromium.org Reported-by: TOTE Robot oslab@tsinghua.edu.cn Link: https://lore.kernel.org/linux-wireless/0e495b14-efbb-e0da-37bd-af6bd677ee2c@... Signed-off-by: Brian Norris briannorris@chromium.org Reviewed-by: Douglas Anderson dianders@chromium.org Signed-off-by: Kalle Valo kvalo@kernel.org Link: https://lore.kernel.org/r/YaV0pllJ5p/EuUat@google.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/marvell/mwifiex/sta_event.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/marvell/mwifiex/sta_event.c b/drivers/net/wireless/marvell/mwifiex/sta_event.c index 5fdffb114913d..fd12093863801 100644 --- a/drivers/net/wireless/marvell/mwifiex/sta_event.c +++ b/drivers/net/wireless/marvell/mwifiex/sta_event.c @@ -364,10 +364,12 @@ static void mwifiex_process_uap_tx_pause(struct mwifiex_private *priv, sta_ptr = mwifiex_get_sta_entry(priv, tp->peermac); if (sta_ptr && sta_ptr->tx_pause != tp->tx_pause) { sta_ptr->tx_pause = tp->tx_pause; + spin_unlock_bh(&priv->sta_list_spinlock); mwifiex_update_ralist_tx_pause(priv, tp->peermac, tp->tx_pause); + } else { + spin_unlock_bh(&priv->sta_list_spinlock); } - spin_unlock_bh(&priv->sta_list_spinlock); } }
@@ -399,11 +401,13 @@ static void mwifiex_process_sta_tx_pause(struct mwifiex_private *priv, sta_ptr = mwifiex_get_sta_entry(priv, tp->peermac); if (sta_ptr && sta_ptr->tx_pause != tp->tx_pause) { sta_ptr->tx_pause = tp->tx_pause; + spin_unlock_bh(&priv->sta_list_spinlock); mwifiex_update_ralist_tx_pause(priv, tp->peermac, tp->tx_pause); + } else { + spin_unlock_bh(&priv->sta_list_spinlock); } - spin_unlock_bh(&priv->sta_list_spinlock); } } }