RDMA/nes: Abnormal listener exit causes loopback node crash

When the listener is destroyed for a loopback connection, the listener
node gets a reset event.  This causes a crash as the listener is not
expecting a reset event.  Code review of cm_event_reset() during
debugging showed the cm_id ref count is incremented after calling its
event handler and not before.

Signed-off-by: Faisal Latif <faisal.latif@intel.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 3 insertions, 13 deletions

diff --git a/drivers/infiniband/hw/nes/nes_cm.c b/drivers/infiniband/hw/nes/nes_cm.c
index ec04786b6069..20e21f1a18b9 100644
--- a/drivers/infiniband/hw/nes/nes_cm.c
+++ b/drivers/infiniband/hw/nes/nes_cm.c
@@ -1014,18 +1014,6 @@ static int mini_cm_dec_refcnt_listen(struct nes_cm_core *cm_core,
                                         cm_node->state = NES_CM_STATE_LISTENER_DESTROYED;
                                         loopback->state = NES_CM_STATE_CLOSED;
 
-                                        event.cm_node = cm_node;
-                                        event.cm_info.rem_addr =
-                                                         cm_node->rem_addr;
-                                        event.cm_info.loc_addr =
-                                                         cm_node->loc_addr;
-                                        event.cm_info.rem_port =
-                                                         cm_node->rem_port;
-                                        event.cm_info.loc_port =
-                                                         cm_node->loc_port;
-                                        event.cm_info.cm_id = cm_node->cm_id;
-                                        cm_event_reset(&event);
-
                                         rem_ref_cm_node(cm_node->cm_core,
                                                          cm_node);
 
@@ -3440,6 +3428,8 @@ static void cm_event_reset(struct nes_cm_event *event)
 
         nes_debug(NES_DBG_CM, "%p - cm_id = %p\n", event->cm_node, cm_id);
         nesqp = cm_id->provider_data;
+        if (!nesqp)
+                return;
 
         nesqp->cm_id = NULL;
         /* cm_id->provider_data = NULL; */
@@ -3451,8 +3441,8 @@ static void cm_event_reset(struct nes_cm_event *event)
         cm_event.private_data = NULL;
         cm_event.private_data_len = 0;
 
-        ret = cm_id->event_handler(cm_id, &cm_event);
         cm_id->add_ref(cm_id);
+        ret = cm_id->event_handler(cm_id, &cm_event);
         atomic_inc(&cm_closes);
         cm_event.event = IW_CM_EVENT_CLOSE;
         cm_event.status = IW_CM_EVENT_STATUS_OK;