IB/mad: Return EPROTONOSUPPORT when an RDMA device lacks the QP required

We had a script which was looping through the devices returned from
ibstat and attempted to register a SMI agent on an ethernet device.
This caused a kernel panic for IBoE devices that don't have QP0.

Fix this by checking if the QP exists before using it.

Signed-off-by: Ira Weiny <weiny2@llnl.gov>
Acked-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index 822cfdcd9f78..b4d8672a3e4e 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -276,6 +276,13 @@ struct ib_mad_agent *ib_register_mad_agent(struct ib_device *device,
                 goto error1;
         }
 
+        /* Verify the QP requested is supported.  For example, Ethernet devices
+         * will not have QP0 */
+        if (!port_priv->qp_info[qpn].qp) {
+                ret = ERR_PTR(-EPROTONOSUPPORT);
+                goto error1;
+        }
+
         /* Allocate structures */
         mad_agent_priv = kzalloc(sizeof *mad_agent_priv, GFP_KERNEL);
         if (!mad_agent_priv) {