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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, Brian Norris <briannorris@chromium.org>,
        Niels Dossche <dossche.niels@gmail.com>,
        Kalle Valo <kvalo@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 009/218] mwifiex: add mutex lock for call in mwifiex_dfs_chan_sw_work_queue
Date:   Mon, 13 Jun 2022 12:07:47 +0200
Message-Id: <20220613094910.533370585@linuxfoundation.org>
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From: Niels Dossche <dossche.niels@gmail.com>

[ Upstream commit 3e12968f6d12a34b540c39cbd696a760cc4616f0 ]

cfg80211_ch_switch_notify uses ASSERT_WDEV_LOCK to assert that
net_device->ieee80211_ptr->mtx (which is the same as priv->wdev.mtx)
is held during the function's execution.
mwifiex_dfs_chan_sw_work_queue is one of its callers, which does not
hold that lock, therefore violating the assertion.
Add a lock around the call.

Disclaimer:
I am currently working on a static analyser to detect missing locks.
This was a reported case. I manually verified the report by looking
at the code, so that I do not send wrong information or patches.
After concluding that this seems to be a true positive, I created
this patch.
However, as I do not in fact have this particular hardware,
I was unable to test it.

Reviewed-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220321225515.32113-1-dossche.niels@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/wireless/marvell/mwifiex/11h.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/11h.c b/drivers/net/wireless/marvell/mwifiex/11h.c
index 238accfe4f41..c4176e357b22 100644
--- a/drivers/net/wireless/marvell/mwifiex/11h.c
+++ b/drivers/net/wireless/marvell/mwifiex/11h.c
@@ -303,5 +303,7 @@ void mwifiex_dfs_chan_sw_work_queue(struct work_struct *work)
 
 	mwifiex_dbg(priv->adapter, MSG,
 		    "indicating channel switch completion to kernel\n");
+	mutex_lock(&priv->wdev.mtx);
 	cfg80211_ch_switch_notify(priv->netdev, &priv->dfs_chandef);
+	mutex_unlock(&priv->wdev.mtx);
 }
-- 
2.35.1