net: ena: fix NULL dereference due to untimely napi initialization

[ Upstream commit 78a55d05def95144ca5fa9a64c49b2a0636a9866 ]

napi poll functions should be initialized before running request_irq(),
to handle a rare condition where there is a pending interrupt, causing
the ISR to fire immediately while the poll function wasn't set yet,
causing a NULL dereference.

Fixes: 1738cd3ed342 ("net: ena: Add a driver for Amazon Elastic Network Adapters (ENA)")
Signed-off-by: Arthur Kiyanovski <akiyano@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/amazon/ena/ena_netdev.c b/drivers/net/ethernet/amazon/ena/ena_netdev.c
index 1d92e03..0c29887 100644 (file)
--- a/drivers/net/ethernet/amazon/ena/ena_netdev.c
+++ b/drivers/net/ethernet/amazon/ena/ena_netdev.c
@@ -1482,8 +1482,6 @@ static int ena_up_complete(struct ena_adapter *adapter)
        if (rc)
                return rc;
 
-       ena_init_napi(adapter);
-
        ena_change_mtu(adapter->netdev, adapter->netdev->mtu);
 
        ena_refill_all_rx_bufs(adapter);
@@ -1643,6 +1641,13 @@ static int ena_up(struct ena_adapter *adapter)
 
        ena_setup_io_intr(adapter);
 
+       /* napi poll functions should be initialized before running
+        * request_irq(), to handle a rare condition where there is a pending
+        * interrupt, causing the ISR to fire immediately while the poll
+        * function wasn't set yet, causing a null dereference
+        */
+       ena_init_napi(adapter);
+
        rc = ena_request_io_irq(adapter);
        if (rc)
                goto err_req_irq;