--- x/net/sched/sch_api.c +++ y/net/sched/sch_api.c @@ -336,17 +336,22 @@ out: return q; } -static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid) +static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid, + struct netlink_ext_ack *extack) { unsigned long cl; const struct Qdisc_class_ops *cops = p->ops->cl_ops; - if (cops == NULL) - return NULL; + if (cops == NULL) { + NL_SET_ERR_MSG(extack, "Parent qdisc is not classful"); + return ERR_PTR(-EOPNOTSUPP); + } cl = cops->find(p, classid); - if (cl == 0) - return NULL; + if (cl == 0) { + NL_SET_ERR_MSG(extack, "Specified class not found"); + return ERR_PTR(-ENOENT); + } return cops->leaf(p, cl); } @@ -1490,16 +1495,20 @@ static int __tc_get_qdisc(struct sk_buff NL_SET_ERR_MSG(extack, "Failed to find qdisc with specified classid"); return -ENOENT; } - q = qdisc_leaf(p, clid); + q = qdisc_leaf(p, clid, extack); } else if (dev_ingress_queue(dev)) { q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping); } } else { q = rtnl_dereference(dev->qdisc); } - if (!q) { - NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device"); - return -ENOENT; + if (IS_ERR_OR_NULL(q)) { + if (!q) { + NL_SET_ERR_MSG(extack, + "Cannot find specified qdisc on specified device"); + return -ENOENT; + } + return PTR_ERR(q); } if (tcm->tcm_handle && q->handle != tcm->tcm_handle) { @@ -1602,7 +1611,9 @@ static int __tc_modify_qdisc(struct sk_b NL_SET_ERR_MSG(extack, "Failed to find specified qdisc"); return -ENOENT; } - q = qdisc_leaf(p, clid); + q = qdisc_leaf(p, clid, extack); + if (IS_ERR(q)) + return PTR_ERR(q); } else if (dev_ingress_queue_create(dev)) { q = rtnl_dereference(dev_ingress_queue(dev)->qdisc_sleeping); }