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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,
        Sukadev Bhattiprolu <sukadev@linux.ibm.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 5.4 226/260] ibmvnic: check failover_pending in login response
Date:   Mon, 20 Sep 2021 18:44:04 +0200
Message-Id: <20210920163938.794105888@linuxfoundation.org>
In-Reply-To: <20210920163931.123590023@linuxfoundation.org>
References: <20210920163931.123590023@linuxfoundation.org>
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From: Sukadev Bhattiprolu <sukadev@linux.ibm.com>

commit 273c29e944bda9a20a30c26cfc34c9a3f363280b upstream.

If a failover occurs before a login response is received, the login
response buffer maybe undefined. Check that there was no failover
before accessing the login response buffer.

Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/ibm/ibmvnic.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -4277,6 +4277,14 @@ static int handle_login_rsp(union ibmvni
 		return 0;
 	}
 
+	if (adapter->failover_pending) {
+		adapter->init_done_rc = -EAGAIN;
+		netdev_dbg(netdev, "Failover pending, ignoring login response\n");
+		complete(&adapter->init_done);
+		/* login response buffer will be released on reset */
+		return 0;
+	}
+
 	netdev->mtu = adapter->req_mtu - ETH_HLEN;
 
 	netdev_dbg(adapter->netdev, "Login Response Buffer:\n");