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2023-12-11 6778948f9de86c3cfaf36725a7c87dcff9ba247f 
 kernel/net/sched/sch_api.c
....@@ -1,10 +1,6 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * net/sched/sch_api.c	Packet scheduler API.
3
- *
4
- *		This program is free software; you can redistribute it and/or
5
- *		modify it under the terms of the GNU General Public License
6
- *		as published by the Free Software Foundation; either version
7
- *		2 of the License, or (at your option) any later version.
84  *
95  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
106  *
....@@ -27,7 +23,6 @@
2723 #include <linux/kmod.h>
2824 #include <linux/list.h>
2925 #include <linux/hrtimer.h>
30
-#include <linux/lockdep.h>
3126 #include <linux/slab.h>
3227 #include <linux/hashtable.h>
3328 
....@@ -36,6 +31,8 @@
3631 #include <net/netlink.h>
3732 #include <net/pkt_sched.h>
3833 #include <net/pkt_cls.h>
34
+
35
+#include <trace/events/qdisc.h>
3936 
4037 /*
4138 
....@@ -270,7 +267,8 @@
270267 	    root->handle == handle)
271268 		return root;
272269 
273
-	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle) {
270
+	hash_for_each_possible_rcu(qdisc_dev(root)->qdisc_hash, q, hash, handle,
271
+				   lockdep_rtnl_is_held()) {
274272 		if (q->handle == handle)
275273 			return q;
276274 	}
....@@ -303,7 +301,7 @@
303301 
304302 	if (!handle)
305303 		return NULL;
306
-	q = qdisc_match_from_root(dev->qdisc, handle);
304
+	q = qdisc_match_from_root(rtnl_dereference(dev->qdisc), handle);
307305 	if (q)
308306 		goto out;
309307 
....@@ -322,7 +320,7 @@
322320 
323321 	if (!handle)
324322 		return NULL;
325
-	q = qdisc_match_from_root(dev->qdisc, handle);
323
+	q = qdisc_match_from_root(rcu_dereference(dev->qdisc), handle);
326324 	if (q)
327325 		goto out;
328326 
....@@ -336,7 +334,6 @@
336334 static struct Qdisc *qdisc_leaf(struct Qdisc *p, u32 classid)
337335 {
338336 	unsigned long cl;
339
-	struct Qdisc *leaf;
340337 	const struct Qdisc_class_ops *cops = p->ops->cl_ops;
341338 
342339 	if (cops == NULL)
....@@ -345,8 +342,7 @@
345342 
346343 	if (cl == 0)
347344 		return NULL;
348
-	leaf = cops->leaf(p, cl);
349
-	return leaf;
345
+	return cops->leaf(p, cl);
350346 }
351347 
352348 /* Find queueing discipline by name */
....@@ -483,7 +479,8 @@
483479 	u16 *tab = NULL;
484480 	int err;
485481 
486
-	err = nla_parse_nested(tb, TCA_STAB_MAX, opt, stab_policy, extack);
482
+	err = nla_parse_nested_deprecated(tb, TCA_STAB_MAX, opt, stab_policy,
483
+					  extack);
487484 	if (err < 0)
488485 		return ERR_PTR(err);
489486 	if (!tb[TCA_STAB_BASE]) {
....@@ -536,11 +533,6 @@
536533 	return stab;
537534 }
538535 
539
-static void stab_kfree_rcu(struct rcu_head *head)
540
-{
541
-	kfree(container_of(head, struct qdisc_size_table, rcu));
542
-}
543
-
544536 void qdisc_put_stab(struct qdisc_size_table *tab)
545537 {
546538 	if (!tab)
....@@ -548,7 +540,7 @@
548540 
549541 	if (--tab->refcnt == 0) {
550542 		list_del(&tab->list);
551
-		call_rcu_bh(&tab->rcu, stab_kfree_rcu);
543
+		kfree_rcu(tab, rcu);
552544 	}
553545 }
554546 EXPORT_SYMBOL(qdisc_put_stab);
....@@ -557,7 +549,7 @@
557549 {
558550 	struct nlattr *nest;
559551 
560
-	nest = nla_nest_start(skb, TCA_STAB);
552
+	nest = nla_nest_start_noflag(skb, TCA_STAB);
561553 	if (nest == NULL)
562554 		goto nla_put_failure;
563555 	if (nla_put(skb, TCA_STAB_BASE, sizeof(stab->szopts), &stab->szopts))
....@@ -636,21 +628,28 @@
636628 }
637629 EXPORT_SYMBOL(qdisc_watchdog_init);
638630 
639
-void qdisc_watchdog_schedule_ns(struct qdisc_watchdog *wd, u64 expires)
631
+void qdisc_watchdog_schedule_range_ns(struct qdisc_watchdog *wd, u64 expires,
632
+				      u64 delta_ns)
640633 {
641634 	if (test_bit(__QDISC_STATE_DEACTIVATED,
642635 		     &qdisc_root_sleeping(wd->qdisc)->state))
643636 		return;
644637 
645
-	if (wd->last_expires == expires)
646
-		return;
638
+	if (hrtimer_is_queued(&wd->timer)) {
639
+		/* If timer is already set in [expires, expires + delta_ns],
640
+		 * do not reprogram it.
641
+		 */
642
+		if (wd->last_expires - expires <= delta_ns)
643
+			return;
644
+	}
647645 
648646 	wd->last_expires = expires;
649
-	hrtimer_start(&wd->timer,
650
-		      ns_to_ktime(expires),
651
-		      HRTIMER_MODE_ABS_PINNED);
647
+	hrtimer_start_range_ns(&wd->timer,
648
+			       ns_to_ktime(expires),
649
+			       delta_ns,
650
+			       HRTIMER_MODE_ABS_PINNED);
652651 }
653
-EXPORT_SYMBOL(qdisc_watchdog_schedule_ns);
652
+EXPORT_SYMBOL(qdisc_watchdog_schedule_range_ns);
654653 
655654 void qdisc_watchdog_cancel(struct qdisc_watchdog *wd)
656655 {
....@@ -768,8 +767,7 @@
768767 	return 0;
769768 }
770769 
771
-void qdisc_tree_reduce_backlog(struct Qdisc *sch, unsigned int n,
772
-			       unsigned int len)
770
+void qdisc_tree_reduce_backlog(struct Qdisc *sch, int n, int len)
773771 {
774772 	bool qdisc_is_offloaded = sch->flags & TCQ_F_OFFLOADED;
775773 	const struct Qdisc_class_ops *cops;
....@@ -817,6 +815,71 @@
817815 	rcu_read_unlock();
818816 }
819817 EXPORT_SYMBOL(qdisc_tree_reduce_backlog);
818
+
819
+int qdisc_offload_dump_helper(struct Qdisc *sch, enum tc_setup_type type,
820
+			      void *type_data)
821
+{
822
+	struct net_device *dev = qdisc_dev(sch);
823
+	int err;
824
+
825
+	sch->flags &= ~TCQ_F_OFFLOADED;
826
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
827
+		return 0;
828
+
829
+	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
830
+	if (err == -EOPNOTSUPP)
831
+		return 0;
832
+
833
+	if (!err)
834
+		sch->flags |= TCQ_F_OFFLOADED;
835
+
836
+	return err;
837
+}
838
+EXPORT_SYMBOL(qdisc_offload_dump_helper);
839
+
840
+void qdisc_offload_graft_helper(struct net_device *dev, struct Qdisc *sch,
841
+				struct Qdisc *new, struct Qdisc *old,
842
+				enum tc_setup_type type, void *type_data,
843
+				struct netlink_ext_ack *extack)
844
+{
845
+	bool any_qdisc_is_offloaded;
846
+	int err;
847
+
848
+	if (!tc_can_offload(dev) || !dev->netdev_ops->ndo_setup_tc)
849
+		return;
850
+
851
+	err = dev->netdev_ops->ndo_setup_tc(dev, type, type_data);
852
+
853
+	/* Don't report error if the graft is part of destroy operation. */
854
+	if (!err || !new || new == &noop_qdisc)
855
+		return;
856
+
857
+	/* Don't report error if the parent, the old child and the new
858
+	 * one are not offloaded.
859
+	 */
860
+	any_qdisc_is_offloaded = new->flags & TCQ_F_OFFLOADED;
861
+	any_qdisc_is_offloaded |= sch && sch->flags & TCQ_F_OFFLOADED;
862
+	any_qdisc_is_offloaded |= old && old->flags & TCQ_F_OFFLOADED;
863
+
864
+	if (any_qdisc_is_offloaded)
865
+		NL_SET_ERR_MSG(extack, "Offloading graft operation failed.");
866
+}
867
+EXPORT_SYMBOL(qdisc_offload_graft_helper);
868
+
869
+static void qdisc_offload_graft_root(struct net_device *dev,
870
+				     struct Qdisc *new, struct Qdisc *old,
871
+				     struct netlink_ext_ack *extack)
872
+{
873
+	struct tc_root_qopt_offload graft_offload = {
874
+		.command	= TC_ROOT_GRAFT,
875
+		.handle		= new ? new->handle : 0,
876
+		.ingress	= (new && new->flags & TCQ_F_INGRESS) ||
877
+				  (old && old->flags & TCQ_F_INGRESS),
878
+	};
879
+
880
+	qdisc_offload_graft_helper(dev, NULL, new, old,
881
+				   TC_SETUP_ROOT_QDISC, &graft_offload, extack);
882
+}
820883 
821884 static int tc_fill_qdisc(struct sk_buff *skb, struct Qdisc *q, u32 clid,
822885 			 u32 portid, u32 seq, u16 flags, int event)
....@@ -949,6 +1012,19 @@
9491012 		qdisc_put(old);
9501013 }
9511014 
1015
+static void qdisc_clear_nolock(struct Qdisc *sch)
1016
+{
1017
+	sch->flags &= ~TCQ_F_NOLOCK;
1018
+	if (!(sch->flags & TCQ_F_CPUSTATS))
1019
+		return;
1020
+
1021
+	free_percpu(sch->cpu_bstats);
1022
+	free_percpu(sch->cpu_qstats);
1023
+	sch->cpu_bstats = NULL;
1024
+	sch->cpu_qstats = NULL;
1025
+	sch->flags &= ~TCQ_F_CPUSTATS;
1026
+}
1027
+
9521028 /* Graft qdisc "new" to class "classid" of qdisc "parent" or
9531029  * to device "dev".
9541030  *
....@@ -965,7 +1041,6 @@
9651041 {
9661042 	struct Qdisc *q = old;
9671043 	struct net *net = dev_net(dev);
968
-	int err = 0;
9691044 
9701045 	if (parent == NULL) {
9711046 		unsigned int i, num_q, ingress;
....@@ -984,6 +1059,8 @@
9841059 
9851060 		if (dev->flags & IFF_UP)
9861061 			dev_deactivate(dev);
1062
+
1063
+		qdisc_offload_graft_root(dev, new, old, extack);
9871064 
9881065 		if (new && new->ops->attach)
9891066 			goto skip;
....@@ -1004,11 +1081,12 @@
10041081 
10051082 skip:
10061083 		if (!ingress) {
1007
-			notify_and_destroy(net, skb, n, classid,
1008
-					   dev->qdisc, new);
1084
+			old = rtnl_dereference(dev->qdisc);
10091085 			if (new && !new->ops->attach)
10101086 				qdisc_refcount_inc(new);
1011
-			dev->qdisc = new ? : &noop_qdisc;
1087
+			rcu_assign_pointer(dev->qdisc, new ? : &noop_qdisc);
1088
+
1089
+			notify_and_destroy(net, skb, n, classid, old, new);
10121090 
10131091 			if (new && new->ops->attach)
10141092 				new->ops->attach(new);
....@@ -1020,28 +1098,28 @@
10201098 			dev_activate(dev);
10211099 	} else {
10221100 		const struct Qdisc_class_ops *cops = parent->ops->cl_ops;
1101
+		unsigned long cl;
1102
+		int err;
10231103 
10241104 		/* Only support running class lockless if parent is lockless */
1025
-		if (new && (new->flags & TCQ_F_NOLOCK) &&
1026
-		    parent && !(parent->flags & TCQ_F_NOLOCK))
1027
-			new->flags &= ~TCQ_F_NOLOCK;
1105
+		if (new && (new->flags & TCQ_F_NOLOCK) && !(parent->flags & TCQ_F_NOLOCK))
1106
+			qdisc_clear_nolock(new);
10281107 
1029
-		err = -EOPNOTSUPP;
1030
-		if (cops && cops->graft) {
1031
-			unsigned long cl = cops->find(parent, classid);
1108
+		if (!cops || !cops->graft)
1109
+			return -EOPNOTSUPP;
10321110 
1033
-			if (cl) {
1034
-				err = cops->graft(parent, cl, new, &old,
1035
-						  extack);
1036
-			} else {
1037
-				NL_SET_ERR_MSG(extack, "Specified class not found");
1038
-				err = -ENOENT;
1039
-			}
1111
+		cl = cops->find(parent, classid);
1112
+		if (!cl) {
1113
+			NL_SET_ERR_MSG(extack, "Specified class not found");
1114
+			return -ENOENT;
10401115 		}
1041
-		if (!err)
1042
-			notify_and_destroy(net, skb, n, classid, old, new);
1116
+
1117
+		err = cops->graft(parent, cl, new, &old, extack);
1118
+		if (err)
1119
+			return err;
1120
+		notify_and_destroy(net, skb, n, classid, old, new);
10431121 	}
1044
-	return err;
1122
+	return 0;
10451123 }
10461124 
10471125 static int qdisc_block_indexes_set(struct Qdisc *sch, struct nlattr **tca,
....@@ -1077,10 +1155,6 @@
10771155 	}
10781156 	return 0;
10791157 }
1080
-
1081
-/* lockdep annotation is needed for ingress; egress gets it only for name */
1082
-static struct lock_class_key qdisc_tx_lock;
1083
-static struct lock_class_key qdisc_rx_lock;
10841158 
10851159 /*
10861160    Allocate and initialize new qdisc.
....@@ -1146,15 +1220,15 @@
11461220 	if (handle == TC_H_INGRESS) {
11471221 		sch->flags |= TCQ_F_INGRESS;
11481222 		handle = TC_H_MAKE(TC_H_INGRESS, 0);
1149
-		lockdep_set_class(qdisc_lock(sch), &qdisc_rx_lock);
11501223 	} else {
11511224 		if (handle == 0) {
11521225 			handle = qdisc_alloc_handle(dev);
1153
-			err = -ENOMEM;
1154
-			if (handle == 0)
1226
+			if (handle == 0) {
1227
+				NL_SET_ERR_MSG(extack, "Maximum number of qdisc handles was exceeded");
1228
+				err = -ENOSPC;
11551229 				goto err_out3;
1230
+			}
11561231 		}
1157
-		lockdep_set_class(qdisc_lock(sch), &qdisc_tx_lock);
11581232 		if (!netif_is_multiqueue(dev))
11591233 			sch->flags |= TCQ_F_ONETXQUEUE;
11601234 	}
....@@ -1219,6 +1293,7 @@
12191293 	}
12201294 
12211295 	qdisc_hash_add(sch, false);
1296
+	trace_qdisc_create(ops, dev, parent);
12221297 
12231298 	return sch;
12241299 
....@@ -1333,8 +1408,7 @@
13331408 }
13341409 
13351410 const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
1336
-	[TCA_KIND]		= { .type = NLA_NUL_STRING,
1337
-				    .len = IFNAMSIZ - 1 },
1411
+	[TCA_KIND]		= { .type = NLA_STRING },
13381412 	[TCA_RATE]		= { .type = NLA_BINARY,
13391413 				    .len = sizeof(struct tc_estimator) },
13401414 	[TCA_STAB]		= { .type = NLA_NESTED },
....@@ -1364,8 +1438,8 @@
13641438 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
13651439 		return -EPERM;
13661440 
1367
-	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
1368
-			  extack);
1441
+	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1442
+				     rtm_tca_policy, extack);
13691443 	if (err < 0)
13701444 		return err;
13711445 
....@@ -1387,7 +1461,7 @@
13871461 				q = dev_ingress_queue(dev)->qdisc_sleeping;
13881462 			}
13891463 		} else {
1390
-			q = dev->qdisc;
1464
+			q = rtnl_dereference(dev->qdisc);
13911465 		}
13921466 		if (!q) {
13931467 			NL_SET_ERR_MSG(extack, "Cannot find specified qdisc on specified device");
....@@ -1449,8 +1523,8 @@
14491523 
14501524 replay:
14511525 	/* Reinit, just in case something touches this. */
1452
-	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
1453
-			  extack);
1526
+	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
1527
+				     rtm_tca_policy, extack);
14541528 	if (err < 0)
14551529 		return err;
14561530 
....@@ -1476,7 +1550,7 @@
14761550 				q = dev_ingress_queue(dev)->qdisc_sleeping;
14771551 			}
14781552 		} else {
1479
-			q = dev->qdisc;
1553
+			q = rtnl_dereference(dev->qdisc);
14801554 		}
14811555 
14821556 		/* It may be default qdisc, ignore it */
....@@ -1684,8 +1758,8 @@
16841758 	idx = 0;
16851759 	ASSERT_RTNL();
16861760 
1687
-	err = nlmsg_parse(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
1688
-			  rtm_tca_policy, NULL);
1761
+	err = nlmsg_parse_deprecated(nlh, sizeof(struct tcmsg), tca, TCA_MAX,
1762
+				     rtm_tca_policy, cb->extack);
16891763 	if (err < 0)
16901764 		return err;
16911765 
....@@ -1698,7 +1772,8 @@
16981772 			s_q_idx = 0;
16991773 		q_idx = 0;
17001774 
1701
-		if (tc_dump_qdisc_root(dev->qdisc, skb, cb, &q_idx, s_q_idx,
1775
+		if (tc_dump_qdisc_root(rtnl_dereference(dev->qdisc),
1776
+				       skb, cb, &q_idx, s_q_idx,
17021777 				       true, tca[TCA_DUMP_INVISIBLE]) < 0)
17031778 			goto done;
17041779 
....@@ -1778,6 +1853,7 @@
17781853 {
17791854 	struct sk_buff *skb;
17801855 	u32 portid = oskb ? NETLINK_CB(oskb).portid : 0;
1856
+	int err = 0;
17811857 
17821858 	skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
17831859 	if (!skb)
....@@ -1788,8 +1864,11 @@
17881864 		return -EINVAL;
17891865 	}
17901866 
1791
-	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1792
-			      n->nlmsg_flags & NLM_F_ECHO);
1867
+	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1868
+			     n->nlmsg_flags & NLM_F_ECHO);
1869
+	if (err > 0)
1870
+		err = 0;
1871
+	return err;
17931872 }
17941873 
17951874 static int tclass_del_notify(struct net *net,
....@@ -1820,8 +1899,11 @@
18201899 		return err;
18211900 	}
18221901 
1823
-	return rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1824
-			      n->nlmsg_flags & NLM_F_ECHO);
1902
+	err = rtnetlink_send(skb, net, portid, RTNLGRP_TC,
1903
+			     n->nlmsg_flags & NLM_F_ECHO);
1904
+	if (err > 0)
1905
+		err = 0;
1906
+	return err;
18251907 }
18261908 
18271909 #ifdef CONFIG_NET_CLS
....@@ -1847,36 +1929,57 @@
18471929 	return 0;
18481930 }
18491931 
1932
+struct tc_bind_class_args {
1933
+	struct qdisc_walker w;
1934
+	unsigned long new_cl;
1935
+	u32 portid;
1936
+	u32 clid;
1937
+};
1938
+
1939
+static int tc_bind_class_walker(struct Qdisc *q, unsigned long cl,
1940
+				struct qdisc_walker *w)
1941
+{
1942
+	struct tc_bind_class_args *a = (struct tc_bind_class_args *)w;
1943
+	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1944
+	struct tcf_block *block;
1945
+	struct tcf_chain *chain;
1946
+
1947
+	block = cops->tcf_block(q, cl, NULL);
1948
+	if (!block)
1949
+		return 0;
1950
+	for (chain = tcf_get_next_chain(block, NULL);
1951
+	     chain;
1952
+	     chain = tcf_get_next_chain(block, chain)) {
1953
+		struct tcf_proto *tp;
1954
+
1955
+		for (tp = tcf_get_next_proto(chain, NULL, true);
1956
+		     tp; tp = tcf_get_next_proto(chain, tp, true)) {
1957
+			struct tcf_bind_args arg = {};
1958
+
1959
+			arg.w.fn = tcf_node_bind;
1960
+			arg.classid = a->clid;
1961
+			arg.base = cl;
1962
+			arg.cl = a->new_cl;
1963
+			tp->ops->walk(tp, &arg.w, true);
1964
+		}
1965
+	}
1966
+
1967
+	return 0;
1968
+}
1969
+
18501970 static void tc_bind_tclass(struct Qdisc *q, u32 portid, u32 clid,
18511971 			   unsigned long new_cl)
18521972 {
18531973 	const struct Qdisc_class_ops *cops = q->ops->cl_ops;
1854
-	struct tcf_block *block;
1855
-	struct tcf_chain *chain;
1856
-	unsigned long cl;
1974
+	struct tc_bind_class_args args = {};
18571975 
1858
-	cl = cops->find(q, portid);
1859
-	if (!cl)
1860
-		return;
18611976 	if (!cops->tcf_block)
18621977 		return;
1863
-	block = cops->tcf_block(q, cl, NULL);
1864
-	if (!block)
1865
-		return;
1866
-	list_for_each_entry(chain, &block->chain_list, list) {
1867
-		struct tcf_proto *tp;
1868
-
1869
-		for (tp = rtnl_dereference(chain->filter_chain);
1870
-		     tp; tp = rtnl_dereference(tp->next)) {
1871
-			struct tcf_bind_args arg = {};
1872
-
1873
-			arg.w.fn = tcf_node_bind;
1874
-			arg.classid = clid;
1875
-			arg.base = cl;
1876
-			arg.cl = new_cl;
1877
-			tp->ops->walk(tp, &arg.w);
1878
-		}
1879
-	}
1978
+	args.portid = portid;
1979
+	args.clid = clid;
1980
+	args.new_cl = new_cl;
1981
+	args.w.fn = tc_bind_class_walker;
1982
+	q->ops->cl_ops->walk(q, &args.w);
18801983 }
18811984 
18821985 #else
....@@ -1908,8 +2011,8 @@
19082011 	    !netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN))
19092012 		return -EPERM;
19102013 
1911
-	err = nlmsg_parse(n, sizeof(*tcm), tca, TCA_MAX, rtm_tca_policy,
1912
-			  extack);
2014
+	err = nlmsg_parse_deprecated(n, sizeof(*tcm), tca, TCA_MAX,
2015
+				     rtm_tca_policy, extack);
19132016 	if (err < 0)
19142017 		return err;
19152018 
....@@ -1946,7 +2049,7 @@
19462049 		} else if (qid1) {
19472050 			qid = qid1;
19482051 		} else if (qid == 0)
1949
-			qid = dev->qdisc->handle;
2052
+			qid = rtnl_dereference(dev->qdisc)->handle;
19502053 
19512054 		/* Now qid is genuine qdisc handle consistent
19522055 		 * both with parent and child.
....@@ -1957,7 +2060,7 @@
19572060 			portid = TC_H_MAKE(qid, portid);
19582061 	} else {
19592062 		if (qid == 0)
1960
-			qid = dev->qdisc->handle;
2063
+			qid = rtnl_dereference(dev->qdisc)->handle;
19612064 	}
19622065 
19632066 	/* OK. Locate qdisc */
....@@ -2118,7 +2221,8 @@
21182221 	s_t = cb->args[0];
21192222 	t = 0;
21202223 
2121
-	if (tc_dump_tclass_root(dev->qdisc, skb, tcm, cb, &t, s_t, true) < 0)
2224
+	if (tc_dump_tclass_root(rtnl_dereference(dev->qdisc),
2225
+				skb, tcm, cb, &t, s_t, true) < 0)
21222226 		goto done;
21232227 
21242228 	dev_queue = dev_ingress_queue(dev);