Index: sys/kern/uipc_usrreq.c
===================================================================
--- sys/kern/uipc_usrreq.c
+++ sys/kern/uipc_usrreq.c
@@ -430,6 +430,8 @@
        unp->unp_socket = so;
        so->so_pcb = unp;
        unp->unp_refcount = 1;
+       if (so->so_head != NULL)
+             unp->unp_flags |= UNP_NASCENT;
 
        UNP_LIST_LOCK();
        unp->unp_gencnt = ++unp_gencnt;
@@ -652,14 +654,21 @@
        unp = sotounpcb(so);
        KASSERT(unp != NULL, ("uipc_detach: unp == NULL"));
 
-       UNP_LINK_WLOCK();
+       vp = NULL;
+       local_unp_rights = 0;
        UNP_LIST_LOCK();
-       UNP_PCB_LOCK(unp);
        LIST_REMOVE(unp, unp_link);
        unp->unp_gencnt = ++unp_gencnt;
        --unp_count;
        UNP_LIST_UNLOCK();
 
+       if ((unp->unp_flags & UNP_NASCENT) != 0) {
+           UNP_PCB_LOCK(unp);
+           goto teardown;
+       }
+       UNP_LINK_WLOCK();
+       UNP_PCB_LOCK(unp);
+
        /*
         * XXXRW: Should assert vp->v_socket == so.
         */
@@ -687,6 +696,7 @@
        }
        local_unp_rights = unp_rights;
        UNP_LINK_WUNLOCK();
+teardown:
        unp->unp_socket->so_pcb = NULL;
        saved_unp_addr = unp->unp_addr;
        unp->unp_addr = NULL;
@@ -1484,6 +1494,7 @@
        case SOCK_STREAM:
        case SOCK_SEQPACKET:
                unp2->unp_conn = unp;
+               unp2->unp_flags &= ~UNP_NASCENT;
                if (req == PRU_CONNECT &&
                    ((unp->unp_flags | unp2->unp_flags) & UNP_CONNWAIT))
                        soisconnecting(so);
Index: sys/sys/unpcb.h
===================================================================
--- sys/sys/unpcb.h
+++ sys/sys/unpcb.h
@@ -115,6 +115,7 @@
  */
 #define        UNP_CONNECTING                  0x010   /* Currently connecting. */
 #define        UNP_BINDING                     0x020   /* Currently binding. */
+#define        UNP_NASCENT                     0x040   /* Newborn child socket. */
 
 #define        sotounpcb(so)   ((struct unpcb *)((so)->so_pcb))