12976 system panics with error in IP module
Reviewed by: Andy Fiddaman <andy@omniosce.org>
Reviewed by: Paul Winder <p.winder@me.com>

*** 20,30 ****
   */
  
  /*
   * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2014, 2017 by Delphix. All rights reserved.
!  * Copyright 2019 Joyent, Inc.
   */
  
  /* This file contains all TCP output processing functions. */
  
  #include <sys/types.h>
--- 20,30 ----
   */
  
  /*
   * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
   * Copyright (c) 2014, 2017 by Delphix. All rights reserved.
!  * Copyright 2020 Joyent, Inc.
   */
  
  /* This file contains all TCP output processing functions. */
  
  #include <sys/types.h>
*** 1675,1689 ****
                  connp->conn_rq = NULL;
                  connp->conn_wq = NULL;
  
                  /* non-STREAM socket, release the upper handle */
                  if (IPCL_IS_NONSTR(connp)) {
!                         ASSERT(connp->conn_upper_handle != NULL);
!                         (*connp->conn_upcalls->su_closed)
!                             (connp->conn_upper_handle);
                          connp->conn_upper_handle = NULL;
                          connp->conn_upcalls = NULL;
                  }
          }
  
          /* Signal tcp_close() to finish closing. */
          mutex_enter(&tcp->tcp_closelock);
--- 1675,1701 ----
                  connp->conn_rq = NULL;
                  connp->conn_wq = NULL;
  
                  /* non-STREAM socket, release the upper handle */
                  if (IPCL_IS_NONSTR(connp)) {
!                         sock_upcalls_t *upcalls = connp->conn_upcalls;
!                         sock_upper_handle_t handle = connp->conn_upper_handle;
! 
!                         ASSERT(upcalls != NULL);
!                         ASSERT(upcalls->su_closed != NULL);
!                         ASSERT(handle != NULL);
!                         /*
!                          * Set these to NULL first because closed() will free
!                          * upper structures.  Acquire conn_lock because an
!                          * external caller like conn_get_socket_info() will
!                          * upcall if these are non-NULL.
!                          */
!                         mutex_enter(&connp->conn_lock);
                          connp->conn_upper_handle = NULL;
                          connp->conn_upcalls = NULL;
+                         mutex_exit(&connp->conn_lock);
+                         upcalls->su_closed(handle);
                  }
          }
  
          /* Signal tcp_close() to finish closing. */
          mutex_enter(&tcp->tcp_closelock);