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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, Pavel Andrianov <andrianov@ispras.ru>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 04/18] net: pxa168_eth: Fix a potential data race in pxa168_eth_remove
Date:   Fri,  9 Apr 2021 11:53:32 +0200
Message-Id: <20210409095301.672498371@linuxfoundation.org>
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From: Pavel Andrianov <andrianov@ispras.ru>

[ Upstream commit 0571a753cb07982cc82f4a5115e0b321da89e1f3 ]

pxa168_eth_remove() firstly calls unregister_netdev(),
then cancels a timeout work. unregister_netdev() shuts down a device
interface and removes it from the kernel tables. If the timeout occurs
in parallel, the timeout work (pxa168_eth_tx_timeout_task) performs stop
and open of the device. It may lead to an inconsistent state and memory
leaks.

Found by Linux Driver Verification project (linuxtesting.org).

Signed-off-by: Pavel Andrianov <andrianov@ispras.ru>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/marvell/pxa168_eth.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/pxa168_eth.c b/drivers/net/ethernet/marvell/pxa168_eth.c
index ff2fea0f8b75..0d6a4e47e7a5 100644
--- a/drivers/net/ethernet/marvell/pxa168_eth.c
+++ b/drivers/net/ethernet/marvell/pxa168_eth.c
@@ -1564,8 +1564,8 @@ static int pxa168_eth_remove(struct platform_device *pdev)
 
 	mdiobus_unregister(pep->smi_bus);
 	mdiobus_free(pep->smi_bus);
-	unregister_netdev(dev);
 	cancel_work_sync(&pep->tx_timeout_task);
+	unregister_netdev(dev);
 	free_netdev(dev);
 	return 0;
 }
-- 
2.30.2