Merge tag 'v5.2-rc7' into rdma.git hmm

Required for dependencies in the next patches.

64 files changed, 458 insertions, 400 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 33824f0385b3..a8d923b5481b 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -71,7 +71,7 @@ obj-$(CONFIG_UTS_NS) += utsname.o
 obj-$(CONFIG_USER_NS) += user_namespace.o
 obj-$(CONFIG_PID_NS) += pid_namespace.o
 obj-$(CONFIG_IKCONFIG) += configs.o
-obj-$(CONFIG_IKHEADERS_PROC) += kheaders.o
+obj-$(CONFIG_IKHEADERS) += kheaders.o
 obj-$(CONFIG_SMP) += stop_machine.o
 obj-$(CONFIG_KPROBES_SANITY_TEST) += test_kprobes.o
 obj-$(CONFIG_AUDIT) += audit.o auditfilter.o
@@ -127,7 +127,7 @@ $(obj)/config_data.gz: $(KCONFIG_CONFIG) FORCE
 $(obj)/kheaders.o: $(obj)/kheaders_data.tar.xz
 
 quiet_cmd_genikh = CHK     $(obj)/kheaders_data.tar.xz
-cmd_genikh = $(CONFIG_SHELL) $(srctree)/kernel/gen_ikh_data.sh $@
+cmd_genikh = $(CONFIG_SHELL) $(srctree)/kernel/gen_kheaders.sh $@
 $(obj)/kheaders_data.tar.xz: FORCE
 	$(call cmd,genikh)
 
diff --git a/kernel/async.c b/kernel/async.c
index 12c332e4e13e..4f9c1d614016 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * async.c: Asynchronous function calls for boot performance
  *
  * (C) Copyright 2009 Intel Corporation
  * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; version 2
- * of the License.
  */
 
 
diff --git a/kernel/backtracetest.c b/kernel/backtracetest.c
index a563c8fdad0d..a2a97fa3071b 100644
--- a/kernel/backtracetest.c
+++ b/kernel/backtracetest.c
@@ -1,13 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Simple stack backtrace regression test module
  *
  * (C) Copyright 2008 Intel Corporation
  * Author: Arjan van de Ven <arjan@linux.intel.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; version 2
- * of the License.
  */
 
 #include <linux/completion.h>
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 584636c9e2eb..262a321f58a6 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  * Copyright (c) 2016,2017 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 #include <linux/bpf.h>
 #include <linux/btf.h>
diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index fcde0f7b2585..92a7d0cf8d13 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -1,11 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Functions to manage eBPF programs attached to cgroups
  *
  * Copyright (c) 2016 Daniel Mack
- *
- * This file is subject to the terms and conditions of version 2 of the GNU
- * General Public License.  See the file COPYING in the main directory of the
- * Linux distribution for more details.
  */
 
 #include <linux/kernel.h>
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c
index 7c473f208a10..080e2bb644cc 100644
--- a/kernel/bpf/core.c
+++ b/kernel/bpf/core.c
@@ -2097,7 +2097,6 @@ int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
 
 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
 EXPORT_SYMBOL(bpf_stats_enabled_key);
-int sysctl_bpf_stats_enabled __read_mostly;
 
 /* All definitions of tracepoints related to BPF. */
 #define CREATE_TRACE_POINTS
diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
index cf727d77c6c6..8ebd0fa826f8 100644
--- a/kernel/bpf/cpumap.c
+++ b/kernel/bpf/cpumap.c
@@ -1,7 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* bpf/cpumap.c
  *
  * Copyright (c) 2017 Jesper Dangaard Brouer, Red Hat Inc.
- * Released under terms in GPL version 2.  See COPYING.
  */
 
 /* The 'cpumap' is primarily used as a backend map for XDP BPF helper
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index 1e525d70f833..cd8297b3bdb9 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -1,13 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 
 /* Devmaps primary use is as a backend map for XDP BPF helper call
@@ -186,6 +178,7 @@ static void dev_map_free(struct bpf_map *map)
 		if (!dev)
 			continue;
 
+		free_percpu(dev->bulkq);
 		dev_put(dev->dev);
 		kfree(dev);
 	}
@@ -281,6 +274,7 @@ void __dev_map_flush(struct bpf_map *map)
 	unsigned long *bitmap = this_cpu_ptr(dtab->flush_needed);
 	u32 bit;
 
+	rcu_read_lock();
 	for_each_set_bit(bit, bitmap, map->max_entries) {
 		struct bpf_dtab_netdev *dev = READ_ONCE(dtab->netdev_map[bit]);
 		struct xdp_bulk_queue *bq;
@@ -291,11 +285,12 @@ void __dev_map_flush(struct bpf_map *map)
 		if (unlikely(!dev))
 			continue;
 
-		__clear_bit(bit, bitmap);
-
 		bq = this_cpu_ptr(dev->bulkq);
 		bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, true);
+
+		__clear_bit(bit, bitmap);
 	}
+	rcu_read_unlock();
 }
 
 /* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or
@@ -388,6 +383,7 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev)
 
 		int cpu;
 
+		rcu_read_lock();
 		for_each_online_cpu(cpu) {
 			bitmap = per_cpu_ptr(dev->dtab->flush_needed, cpu);
 			__clear_bit(dev->bit, bitmap);
@@ -395,6 +391,7 @@ static void dev_map_flush_old(struct bpf_dtab_netdev *dev)
 			bq = per_cpu_ptr(dev->bulkq, cpu);
 			bq_xmit_all(dev, bq, XDP_XMIT_FLUSH, false);
 		}
+		rcu_read_unlock();
 	}
 }
 
diff --git a/kernel/bpf/disasm.c b/kernel/bpf/disasm.c
index d9ce383c0f9c..b44d8c447afd 100644
--- a/kernel/bpf/disasm.c
+++ b/kernel/bpf/disasm.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  * Copyright (c) 2016 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 
 #include <linux/bpf.h>
diff --git a/kernel/bpf/disasm.h b/kernel/bpf/disasm.h
index e1324a834a24..e546b18d27da 100644
--- a/kernel/bpf/disasm.h
+++ b/kernel/bpf/disasm.h
@@ -1,14 +1,6 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  * Copyright (c) 2016 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 
 #ifndef __BPF_DISASM_H__
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c
index 0f2708fde5f7..583df5cb302d 100644
--- a/kernel/bpf/hashtab.c
+++ b/kernel/bpf/hashtab.c
@@ -1,14 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  * Copyright (c) 2016 Facebook
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 #include <linux/bpf.h>
 #include <linux/btf.h>
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 4266ffde07ca..5e28718928ca 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -1,13 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 #include <linux/bpf.h>
 #include <linux/rcupdate.h>
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index 84a80b02db99..cc0d0cf114e3 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Minimal file system backend for holding eBPF maps and programs,
  * used by bpf(2) object pinning.
@@ -5,10 +6,6 @@
  * Authors:
  *
  *	Daniel Borkmann <daniel@iogearbox.net>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
  */
 
 #include <linux/init.h>
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index e61630c2e50b..57b59cca4db7 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Longest prefix match list implementation
  *
  * Copyright (c) 2016,2017 Daniel Mack
  * Copyright (c) 2016 David Herrmann
- *
- * This file is subject to the terms and conditions of version 2 of the GNU
- * General Public License.  See the file COPYING in the main directory of the
- * Linux distribution for more details.
  */
 
 #include <linux/bpf.h>
@@ -716,9 +713,14 @@ find_leftmost:
 	 * have exact two children, so this function will never return NULL.
 	 */
 	for (node = search_root; node;) {
-		if (!(node->flags & LPM_TREE_NODE_FLAG_IM))
+		if (node->flags & LPM_TREE_NODE_FLAG_IM) {
+			node = rcu_dereference(node->child[0]);
+		} else {
 			next_node = node;
-		node = rcu_dereference(node->child[0]);
+			node = rcu_dereference(node->child[0]);
+			if (!node)
+				node = rcu_dereference(next_node->child[1]);
+		}
 	}
 do_copy:
 	next_key->prefixlen = next_node->prefixlen;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index cb5440b02e82..42d17f730780 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1,13 +1,5 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 #include <linux/bpf.h>
 #include <linux/bpf_trace.h>
@@ -1581,6 +1573,8 @@ bpf_prog_load_check_attach_type(enum bpf_prog_type prog_type,
 		case BPF_CGROUP_INET6_CONNECT:
 		case BPF_CGROUP_UDP4_SENDMSG:
 		case BPF_CGROUP_UDP6_SENDMSG:
+		case BPF_CGROUP_UDP4_RECVMSG:
+		case BPF_CGROUP_UDP6_RECVMSG:
 			return 0;
 		default:
 			return -EINVAL;
@@ -1875,6 +1869,8 @@ static int bpf_prog_attach(const union bpf_attr *attr)
 	case BPF_CGROUP_INET6_CONNECT:
 	case BPF_CGROUP_UDP4_SENDMSG:
 	case BPF_CGROUP_UDP6_SENDMSG:
+	case BPF_CGROUP_UDP4_RECVMSG:
+	case BPF_CGROUP_UDP6_RECVMSG:
 		ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
 		break;
 	case BPF_CGROUP_SOCK_OPS:
@@ -1960,6 +1956,8 @@ static int bpf_prog_detach(const union bpf_attr *attr)
 	case BPF_CGROUP_INET6_CONNECT:
 	case BPF_CGROUP_UDP4_SENDMSG:
 	case BPF_CGROUP_UDP6_SENDMSG:
+	case BPF_CGROUP_UDP4_RECVMSG:
+	case BPF_CGROUP_UDP6_RECVMSG:
 		ptype = BPF_PROG_TYPE_CGROUP_SOCK_ADDR;
 		break;
 	case BPF_CGROUP_SOCK_OPS:
@@ -2011,6 +2009,8 @@ static int bpf_prog_query(const union bpf_attr *attr,
 	case BPF_CGROUP_INET6_CONNECT:
 	case BPF_CGROUP_UDP4_SENDMSG:
 	case BPF_CGROUP_UDP6_SENDMSG:
+	case BPF_CGROUP_UDP4_RECVMSG:
+	case BPF_CGROUP_UDP6_RECVMSG:
 	case BPF_CGROUP_SOCK_OPS:
 	case BPF_CGROUP_DEVICE:
 	case BPF_CGROUP_SYSCTL:
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 95f9354495ad..a5c369e60343 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -1,15 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  * Copyright (c) 2016 Facebook
  * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
  */
 #include <uapi/linux/btf.h>
 #include <linux/kernel.h>
@@ -5361,9 +5353,12 @@ static int check_return_code(struct bpf_verifier_env *env)
 	struct tnum range = tnum_range(0, 1);
 
 	switch (env->prog->type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+		if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
+		    env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG)
+			range = tnum_range(1, 1);
 	case BPF_PROG_TYPE_CGROUP_SKB:
 	case BPF_PROG_TYPE_CGROUP_SOCK:
-	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
 	case BPF_PROG_TYPE_SOCK_OPS:
 	case BPF_PROG_TYPE_CGROUP_DEVICE:
 	case BPF_PROG_TYPE_CGROUP_SYSCTL:
@@ -5380,16 +5375,17 @@ static int check_return_code(struct bpf_verifier_env *env)
 	}
 
 	if (!tnum_in(range, reg->var_off)) {
+		char tn_buf[48];
+
 		verbose(env, "At program exit the register R0 ");
 		if (!tnum_is_unknown(reg->var_off)) {
-			char tn_buf[48];
-
 			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
 			verbose(env, "has value %s", tn_buf);
 		} else {
 			verbose(env, "has unknown scalar value");
 		}
-		verbose(env, " should have been 0 or 1\n");
+		tnum_strn(tn_buf, sizeof(tn_buf), range);
+		verbose(env, " should have been in %s\n", tn_buf);
 		return -EINVAL;
 	}
 	return 0;
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 426a0026225c..bf9dbffd46b1 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -215,7 +215,8 @@ static struct cftype cgroup_base_files[];
 
 static int cgroup_apply_control(struct cgroup *cgrp);
 static void cgroup_finalize_control(struct cgroup *cgrp, int ret);
-static void css_task_iter_advance(struct css_task_iter *it);
+static void css_task_iter_skip(struct css_task_iter *it,
+			       struct task_struct *task);
 static int cgroup_destroy_locked(struct cgroup *cgrp);
 static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
 					      struct cgroup_subsys *ss);
@@ -738,6 +739,7 @@ struct css_set init_css_set = {
 	.dom_cset		= &init_css_set,
 	.tasks			= LIST_HEAD_INIT(init_css_set.tasks),
 	.mg_tasks		= LIST_HEAD_INIT(init_css_set.mg_tasks),
+	.dying_tasks		= LIST_HEAD_INIT(init_css_set.dying_tasks),
 	.task_iters		= LIST_HEAD_INIT(init_css_set.task_iters),
 	.threaded_csets		= LIST_HEAD_INIT(init_css_set.threaded_csets),
 	.cgrp_links		= LIST_HEAD_INIT(init_css_set.cgrp_links),
@@ -843,6 +845,21 @@ static void css_set_update_populated(struct css_set *cset, bool populated)
 		cgroup_update_populated(link->cgrp, populated);
 }
 
+/*
+ * @task is leaving, advance task iterators which are pointing to it so
+ * that they can resume at the next position.  Advancing an iterator might
+ * remove it from the list, use safe walk.  See css_task_iter_skip() for
+ * details.
+ */
+static void css_set_skip_task_iters(struct css_set *cset,
+				    struct task_struct *task)
+{
+	struct css_task_iter *it, *pos;
+
+	list_for_each_entry_safe(it, pos, &cset->task_iters, iters_node)
+		css_task_iter_skip(it, task);
+}
+
 /**
  * css_set_move_task - move a task from one css_set to another
  * @task: task being moved
@@ -868,22 +885,9 @@ static void css_set_move_task(struct task_struct *task,
 		css_set_update_populated(to_cset, true);
 
 	if (from_cset) {
-		struct css_task_iter *it, *pos;
-
 		WARN_ON_ONCE(list_empty(&task->cg_list));
 
-		/*
-		 * @task is leaving, advance task iterators which are
-		 * pointing to it so that they can resume at the next
-		 * position.  Advancing an iterator might remove it from
-		 * the list, use safe walk.  See css_task_iter_advance*()
-		 * for details.
-		 */
-		list_for_each_entry_safe(it, pos, &from_cset->task_iters,
-					 iters_node)
-			if (it->task_pos == &task->cg_list)
-				css_task_iter_advance(it);
-
+		css_set_skip_task_iters(from_cset, task);
 		list_del_init(&task->cg_list);
 		if (!css_set_populated(from_cset))
 			css_set_update_populated(from_cset, false);
@@ -1210,6 +1214,7 @@ static struct css_set *find_css_set(struct css_set *old_cset,
 	cset->dom_cset = cset;
 	INIT_LIST_HEAD(&cset->tasks);
 	INIT_LIST_HEAD(&cset->mg_tasks);
+	INIT_LIST_HEAD(&cset->dying_tasks);
 	INIT_LIST_HEAD(&cset->task_iters);
 	INIT_LIST_HEAD(&cset->threaded_csets);
 	INIT_HLIST_NODE(&cset->hlist);
@@ -4408,15 +4413,18 @@ static void css_task_iter_advance_css_set(struct css_task_iter *it)
 			it->task_pos = NULL;
 			return;
 		}
-	} while (!css_set_populated(cset));
+	} while (!css_set_populated(cset) && list_empty(&cset->dying_tasks));
 
 	if (!list_empty(&cset->tasks))
 		it->task_pos = cset->tasks.next;
-	else
+	else if (!list_empty(&cset->mg_tasks))
 		it->task_pos = cset->mg_tasks.next;
+	else
+		it->task_pos = cset->dying_tasks.next;
 
 	it->tasks_head = &cset->tasks;
 	it->mg_tasks_head = &cset->mg_tasks;
+	it->dying_tasks_head = &cset->dying_tasks;
 
 	/*
 	 * We don't keep css_sets locked across iteration steps and thus
@@ -4442,9 +4450,20 @@ static void css_task_iter_advance_css_set(struct css_task_iter *it)
 	list_add(&it->iters_node, &cset->task_iters);
 }
 
+static void css_task_iter_skip(struct css_task_iter *it,
+			       struct task_struct *task)
+{
+	lockdep_assert_held(&css_set_lock);
+
+	if (it->task_pos == &task->cg_list) {
+		it->task_pos = it->task_pos->next;
+		it->flags |= CSS_TASK_ITER_SKIPPED;
+	}
+}
+
 static void css_task_iter_advance(struct css_task_iter *it)