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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, Netanel Belgazal <netanel@amazon.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <alexander.levin@microsoft.com>
Subject: [PATCH 4.18 118/168] net: ena: fix surprise unplug NULL dereference kernel crash
Date:   Mon,  8 Oct 2018 20:31:38 +0200
Message-Id: <20181008175624.531580718@linuxfoundation.org>
In-Reply-To: <20181008175620.043587728@linuxfoundation.org>
References: <20181008175620.043587728@linuxfoundation.org>
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4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Netanel Belgazal <netanel@amazon.com>

[ Upstream commit 772ed869f535b4ec2b134645c951ff22de4d3f79 ]

Starting with driver version 1.5.0, in case of a surprise device
unplug, there is a race caused by invoking ena_destroy_device()
from two different places. As a result, the readless register might
be accessed after it was destroyed.

Signed-off-by: Netanel Belgazal <netanel@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -3408,12 +3408,12 @@ static void ena_remove(struct pci_dev *p
 		netdev->rx_cpu_rmap = NULL;
 	}
 #endif /* CONFIG_RFS_ACCEL */
-
-	unregister_netdev(netdev);
 	del_timer_sync(&adapter->timer_service);
 
 	cancel_work_sync(&adapter->reset_task);
 
+	unregister_netdev(netdev);
+
 	/* Reset the device only if the device is running. */
 	if (test_bit(ENA_FLAG_DEVICE_RUNNING, &adapter->flags))
 		ena_com_dev_reset(ena_dev, adapter->reset_reason);