[PATCH] infiniband/i40iw: Fix a use after free in i40iw_cm_event_handler

[Lv Yunlong]

In the case of I40IW_CM_EVENT_ABORTED, i40iw_event_connect_error()
could be called to free the event->cm_node. However, event->cm_node
will be used after and cause use after free. It needs to add flags
to inform that event->cm_node has been freed.

Signed-off-by: Lv Yunlong <lyl2...@mail.ustc.edu.cn>
---
 drivers/infiniband/hw/i40iw/i40iw_cm.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/hw/i40iw/i40iw_cm.c 
b/drivers/infiniband/hw/i40iw/i40iw_cm.c
index ac65c8237b2e..447b43c2d21f 100644
--- a/drivers/infiniband/hw/i40iw/i40iw_cm.c
+++ b/drivers/infiniband/hw/i40iw/i40iw_cm.c
@@ -4175,6 +4175,7 @@ static void i40iw_cm_event_handler(struct work_struct 
*work)
                                                    struct i40iw_cm_event,
                                                    event_work);
        struct i40iw_cm_node *cm_node;
+       int flags = 0;
 
        if (!event || !event->cm_node || !event->cm_node->cm_core)
                return;
@@ -4211,6 +4212,7 @@ static void i40iw_cm_event_handler(struct work_struct 
*work)
                    (event->cm_node->state == I40IW_CM_STATE_OFFLOADED))
                        break;
                i40iw_event_connect_error(event);
+               flags = 1;
                break;
        default:
                i40iw_pr_err("event type = %d\n", event->type);
@@ -4218,7 +4220,8 @@ static void i40iw_cm_event_handler(struct work_struct 
*work)
        }
 
        event->cm_info.cm_id->rem_ref(event->cm_info.cm_id);
-       i40iw_rem_ref_cm_node(event->cm_node);
+       if (!flags)
+               i40iw_rem_ref_cm_node(event->cm_node);
        kfree(event);
 }
 
-- 
2.25.1