netdev - [PATCH net V2 1/7] net: ena: fix surprise unplug NULL dereference kernel crash

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Date:   Sun, 9 Sep 2018 08:15:20 +0000
From:   <netanel@...zon.com>
To:     <davem@...emloft.net>, <netdev@...r.kernel.org>
CC:     Netanel Belgazal <netanel@...zon.com>, <dwmw@...zon.com>,
        <zorik@...zon.com>, <matua@...zon.com>, <saeedb@...zon.com>,
        <msw@...zon.com>, <aliguori@...zon.com>, <nafea@...zon.com>,
        <evgenys@...zon.com>, <gtzalik@...zon.com>
Subject: [PATCH net V2 1/7] net: ena: fix surprise unplug NULL dereference kernel crash

From: Netanel Belgazal <netanel@...zon.com>

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@...zon.com>
---
 drivers/net/ethernet/amazon/ena/ena_netdev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index c673ac2df65b..170830b807fe 100644
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -3409,12 +3409,12 @@ static void ena_remove(struct pci_dev *pdev)
 		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);
-- 
2.15.2.AMZN