diff --git a/src/checks.c b/src/checks.c
index 2c2ee7e..f24e1fa 100644
--- a/src/checks.c
+++ b/src/checks.c
@@ -1465,6 +1465,7 @@
 						fdtab[fd].owner = t;
 						fdtab[fd].cb[DIR_RD].f = &event_srv_chk_r;
 						fdtab[fd].cb[DIR_WR].f = &event_srv_chk_w;
+						fdtab[fd].iocb = NULL;
 						fdtab[fd].flags = FD_FL_TCP | FD_FL_TCP_NODELAY;
 						EV_FD_SET(fd, DIR_WR);  /* for connect status */
 #ifdef DEBUG_FULL
diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index ddc8269..41a31b8 100644
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -476,10 +476,12 @@
 	if ((si->ob->flags & BF_OUT_EMPTY) || si->send_proxy_ofs) {
 		fdtab[fd].cb[DIR_RD].f = tcp_connect_read;
 		fdtab[fd].cb[DIR_WR].f = tcp_connect_write;
+		fdtab[fd].iocb = NULL;
 	}
 	else {
 		fdtab[fd].cb[DIR_RD].f = si_data(si)->read;
 		fdtab[fd].cb[DIR_WR].f = si_data(si)->write;
+		fdtab[fd].iocb = NULL;
 	}
 
 	fd_insert(fd);
@@ -821,6 +823,7 @@
 	fdtab[fd].flags = FD_FL_TCP | ((listener->options & LI_O_NOLINGER) ? FD_FL_TCP_NOLING : 0);
 	fdtab[fd].cb[DIR_RD].f = listener->proto->accept;
 	fdtab[fd].cb[DIR_WR].f = NULL; /* never called */
+	fdtab[fd].iocb = NULL;
 	fd_insert(fd);
 
  tcp_return:
diff --git a/src/proto_uxst.c b/src/proto_uxst.c
index f637601..2dc5613 100644
--- a/src/proto_uxst.c
+++ b/src/proto_uxst.c
@@ -264,6 +264,7 @@
 	fd_insert(fd);
 	fdtab[fd].cb[DIR_RD].f = listener->proto->accept;
 	fdtab[fd].cb[DIR_WR].f = NULL; /* never called */
+	fdtab[fd].iocb = NULL;
 	fdtab[fd].owner = listener; /* reference the listener instead of a task */
 	return ERR_NONE;
  err_rename:
diff --git a/src/session.c b/src/session.c
index c67d85e..0b0c3da 100644
--- a/src/session.c
+++ b/src/session.c
@@ -284,6 +284,7 @@
 	fdtab[cfd].flags = 0;
 	fdtab[cfd].cb[DIR_RD].f = si_data(&s->si[0])->read;
 	fdtab[cfd].cb[DIR_WR].f = si_data(&s->si[0])->write;
+	fdtab[cfd].iocb = NULL;
 	EV_FD_SET(cfd, DIR_RD);
 
 	if (p->accept && (ret = p->accept(s)) <= 0) {