ibmvnic: track pending login

If after ibmvnic sends a LOGIN it gets a FAILOVER, it is possible that
the worker thread will start reset process and free the login response
buffer before it gets a (now stale) LOGIN_RSP. The ibmvnic tasklet will
then try to access the login response buffer and crash.

Have ibmvnic track pending logins and discard any stale login responses.

Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index d4d40b3..13eae16 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -3841,6 +3841,8 @@ static int send_login(struct ibmvnic_adapter *adapter)
        crq.login.cmd = LOGIN;
        crq.login.ioba = cpu_to_be32(buffer_token);
        crq.login.len = cpu_to_be32(buffer_size);
+
+       adapter->login_pending = true;
        ibmvnic_send_crq(adapter, &crq);
 
        return 0;
@@ -4393,6 +4395,15 @@ static int handle_login_rsp(union ibmvnic_crq *login_rsp_crq,
        u64 *size_array;
        int i;
 
+       /* CHECK: Test/set of login_pending does not need to be atomic
+        * because only ibmvnic_tasklet tests/clears this.
+        */
+       if (!adapter->login_pending) {
+               netdev_warn(netdev, "Ignoring unexpected login response\n");
+               return 0;
+       }
+       adapter->login_pending = false;
+
        dma_unmap_single(dev, adapter->login_buf_token, adapter->login_buf_sz,
                         DMA_TO_DEVICE);
        dma_unmap_single(dev, adapter->login_rsp_buf_token,
@@ -4764,6 +4775,11 @@ static void ibmvnic_handle_crq(union ibmvnic_crq *crq,
                case IBMVNIC_CRQ_INIT:
                        dev_info(dev, "Partner initialized\n");
                        adapter->from_passive_init = true;
+                       /* Discard any stale login responses from prev reset.
+                        * CHECK: should we clear even on INIT_COMPLETE?
+                        */
+                       adapter->login_pending = false;
+
                        if (!completion_done(&adapter->init_done)) {
                                complete(&adapter->init_done);
                                adapter->init_done_rc = -EIO;
@@ -5196,6 +5212,7 @@ static int ibmvnic_probe(struct vio_dev *dev, const struct vio_device_id *id)
        dev_set_drvdata(&dev->dev, netdev);
        adapter->vdev = dev;
        adapter->netdev = netdev;
+       adapter->login_pending = false;
 
        ether_addr_copy(adapter->mac_addr, mac_addr_p);
        ether_addr_copy(netdev->dev_addr, adapter->mac_addr);

diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index 47a3fd7..bffa7f9 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -1086,6 +1086,7 @@ struct ibmvnic_adapter {
        struct delayed_work ibmvnic_delayed_reset;
        unsigned long resetting;
        bool napi_enabled, from_passive_init;
+       bool login_pending;
 
        bool failover_pending;
        bool force_reset_recovery;