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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, YN Chen <YN.Chen@mediatek.com>,
        Sean Wang <sean.wang@mediatek.com>,
        Felix Fietkau <nbd@nbd.name>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.0 278/862] wifi: mt76: sdio: fix the deadlock caused by sdio->stat_work
Date:   Wed, 19 Oct 2022 10:26:05 +0200
Message-Id: <20221019083302.305602434@linuxfoundation.org>
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From: Sean Wang <sean.wang@mediatek.com>

[ Upstream commit e5d78fd998be94fb459a3d625df7367849b997b8 ]

Because wake_work and sdio->stat_work share the same workqueue mt76->wq,
if sdio->stat_work cannot acquire the mutex lock such as that was possibly
held up by [mt7615, mt7921]_mutex_acquire. Additionally, if
[mt7615, mt7921]_mutex_acquire was called by sdio->stat_work self, the wake
would be blocked by itself. Thus, we move the stat_work into
ieee80211_workqueue instead to break the deadlock.

Fixes: d39b52e31aa6 ("mt76: introduce mt76_sdio module")
Co-developed-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: YN Chen <YN.Chen@mediatek.com>
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/mediatek/mt76/sdio.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/sdio.c b/drivers/net/wireless/mediatek/mt76/sdio.c
index aba2a9865821..fb2caeae6dba 100644
--- a/drivers/net/wireless/mediatek/mt76/sdio.c
+++ b/drivers/net/wireless/mediatek/mt76/sdio.c
@@ -481,7 +481,7 @@ static void mt76s_status_worker(struct mt76_worker *w)
 		if (dev->drv->tx_status_data &&
 		    !test_and_set_bit(MT76_READING_STATS, &dev->phy.state) &&
 		    !test_bit(MT76_STATE_SUSPEND, &dev->phy.state))
-			queue_work(dev->wq, &dev->sdio.stat_work);
+			ieee80211_queue_work(dev->hw, &dev->sdio.stat_work);
 	} while (nframes > 0);
 
 	if (resched)
@@ -508,7 +508,7 @@ static void mt76s_tx_status_data(struct work_struct *work)
 	}
 
 	if (count && test_bit(MT76_STATE_RUNNING, &dev->phy.state))
-		queue_work(dev->wq, &sdio->stat_work);
+		ieee80211_queue_work(dev->hw, &sdio->stat_work);
 	else
 		clear_bit(MT76_READING_STATS, &dev->phy.state);
 }
-- 
2.35.1