From f6f4de69c786a2d089a083a0e6cb05e4a43b5dc1 Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Mon, 29 Nov 2021 16:47:34 -0800 Subject: [PATCH] mwifiex: Fix possible ABBA deadlock BugLink: https://bugs.launchpad.net/bugs/1959376 [ Upstream commit 1b8bb8919ef81bfc8873d223b9361f1685f2106d ] Quoting Jia-Ju Bai : 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 Reported-by: TOTE Robot Link: https://lore.kernel.org/linux-wireless/0e495b14-efbb-e0da-37bd-af6bd677ee2c@gmail.com/ Signed-off-by: Brian Norris Reviewed-by: Douglas Anderson Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/YaV0pllJ5p/EuUat@google.com Signed-off-by: Sasha Levin Signed-off-by: Paolo Pisati --- 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 68c63268e2e6..2b2e6e0166e1 100644 --- a/drivers/net/wireless/marvell/mwifiex/sta_event.c +++ b/drivers/net/wireless/marvell/mwifiex/sta_event.c @@ -365,10 +365,12 @@ 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); } } @@ -400,11 +402,13 @@ 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); } } } -- 2.39.5