IB/cm: Check cm_id state before handling a REP

Move checking the state of a cm_id before modifying it when handling a
REP.  This fixes a bug seen under MPI scale-up testing, where a NULL
timewait_info pointer is dereferenced if a request times out before a
REP is received.

Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 2514de3..7cfedb8 100644 (file)
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -121,7 +121,7 @@ struct cm_id_private {
 
        struct rb_node service_node;
        struct rb_node sidr_id_node;
-       spinlock_t lock;
+       spinlock_t lock;        /* Do not acquire inside cm.lock */
        wait_queue_head_t wait;
        atomic_t refcount;
 
@@ -1547,40 +1547,46 @@ static int cm_rep_handler(struct cm_work *work)
                return -EINVAL;
        }
 
+       cm_format_rep_event(work);
+
+       spin_lock_irqsave(&cm_id_priv->lock, flags);
+       switch (cm_id_priv->id.state) {
+       case IB_CM_REQ_SENT:
+       case IB_CM_MRA_REQ_RCVD:
+               break;
+       default:
+               spin_unlock_irqrestore(&cm_id_priv->lock, flags);
+               ret = -EINVAL;
+               goto error;
+       }
+
        cm_id_priv->timewait_info->work.remote_id = rep_msg->local_comm_id;
        cm_id_priv->timewait_info->remote_ca_guid = rep_msg->local_ca_guid;
        cm_id_priv->timewait_info->remote_qpn = cm_rep_get_local_qpn(rep_msg);
 
-       spin_lock_irqsave(&cm.lock, flags);
+       spin_lock(&cm.lock);
        /* Check for duplicate REP. */
        if (cm_insert_remote_id(cm_id_priv->timewait_info)) {
-               spin_unlock_irqrestore(&cm.lock, flags);
+               spin_unlock(&cm.lock);
+               spin_unlock_irqrestore(&cm_id_priv->lock, flags);
                ret = -EINVAL;
                goto error;
        }
        /* Check for a stale connection. */
        if (cm_insert_remote_qpn(cm_id_priv->timewait_info)) {
-               spin_unlock_irqrestore(&cm.lock, flags);
+               rb_erase(&cm_id_priv->timewait_info->remote_id_node,
+                        &cm.remote_id_table);
+               cm_id_priv->timewait_info->inserted_remote_id = 0;
+               spin_unlock(&cm.lock);
+               spin_unlock_irqrestore(&cm_id_priv->lock, flags);
                cm_issue_rej(work->port, work->mad_recv_wc,
                             IB_CM_REJ_STALE_CONN, CM_MSG_RESPONSE_REP,
                             NULL, 0);
                ret = -EINVAL;
                goto error;
        }
-       spin_unlock_irqrestore(&cm.lock, flags);
-
-       cm_format_rep_event(work);
+       spin_unlock(&cm.lock);
 
-       spin_lock_irqsave(&cm_id_priv->lock, flags);
-       switch (cm_id_priv->id.state) {
-       case IB_CM_REQ_SENT:
-       case IB_CM_MRA_REQ_RCVD:
-               break;
-       default:
-               spin_unlock_irqrestore(&cm_id_priv->lock, flags);
-               ret = -EINVAL;
-               goto error;
-       }
        cm_id_priv->id.state = IB_CM_REP_RCVD;
        cm_id_priv->id.remote_id = rep_msg->local_comm_id;
        cm_id_priv->remote_qpn = cm_rep_get_local_qpn(rep_msg);
@@ -1603,7 +1609,7 @@ static int cm_rep_handler(struct cm_work *work)
                cm_deref_id(cm_id_priv);
        return 0;
 
-error: cm_cleanup_timewait(cm_id_priv->timewait_info);
+error:
        cm_deref_id(cm_id_priv);
        return ret;
 }