[PATCH net v2] ibmvnic fix NULL tx_pools and rx_tools issue at do_reset

[Dany Madden]

From: Mingming Cao <m...@linux.vnet.ibm.com>

At the time of do_rest, ibmvnic tries to re-initalize the tx_pools
and rx_pools to avoid re-allocating the long term buffer. However
there is a window inside do_reset that the tx_pools and
rx_pools were freed before re-initialized making it possible to deference
null pointers.

This patch fix this issue by always check the tx_pool
and rx_pool are not NULL after ibmvnic_login. If so, re-allocating
the pools. This will avoid getting into calling reset_tx/rx_pools with
NULL adapter tx_pools/rx_pools pointer. Also add null pointer check in
reset_tx_pools and reset_rx_pools to safe handle NULL pointer case.

Signed-off-by: Mingming Cao <m...@linux.vnet.ibm.com>
Signed-off-by: Dany Madden <d...@linux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c 
b/drivers/net/ethernet/ibm/ibmvnic.c
index 5afb3c9c52d2..52feee97821e 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -479,6 +479,9 @@ static int reset_rx_pools(struct ibmvnic_adapter *adapter)
        int i, j, rc;
        u64 *size_array;
 
+       if (!adapter->rx_pool)
+               return -1;
+
        size_array = (u64 *)((u8 *)(adapter->login_rsp_buf) +
                be32_to_cpu(adapter->login_rsp_buf->off_rxadd_buff_size));
 
@@ -649,6 +652,9 @@ static int reset_tx_pools(struct ibmvnic_adapter *adapter)
        int tx_scrqs;
        int i, rc;
 
+       if (!adapter->tx_pool)
+               return -1;
+
        tx_scrqs = be32_to_cpu(adapter->login_rsp_buf->num_txsubm_subcrqs);
        for (i = 0; i < tx_scrqs; i++) {
                rc = reset_one_tx_pool(adapter, &adapter->tso_pool[i]);
@@ -2011,7 +2017,10 @@ static int do_reset(struct ibmvnic_adapter *adapter,
                    adapter->req_rx_add_entries_per_subcrq !=
                    old_num_rx_slots ||
                    adapter->req_tx_entries_per_subcrq !=
-                   old_num_tx_slots) {
+                   old_num_tx_slots ||
+                       !adapter->rx_pool ||
+                       !adapter->tso_pool ||
+                       !adapter->tx_pool) {
                        release_rx_pools(adapter);
                        release_tx_pools(adapter);
                        release_napi(adapter);
@@ -2024,10 +2033,14 @@ static int do_reset(struct ibmvnic_adapter *adapter,
                } else {
                        rc = reset_tx_pools(adapter);
                        if (rc)
+                               netdev_dbg(adapter->netdev, "reset tx pools 
failed (%d)\n",
+                                               rc);
                                goto out;
 
                        rc = reset_rx_pools(adapter);
                        if (rc)
+                               netdev_dbg(adapter->netdev, "reset rx pools 
failed (%d)\n",
+                                               rc);
                                goto out;
                }
                ibmvnic_disable_irqs(adapter);
-- 
2.18.2