Merge v7.1.5linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 4 deletions

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index b5314c9fed3c..c2032af98e08 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -2295,6 +2295,7 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root,
 		      struct bpf_spin_lock *spin_lock)
 {
 	struct rb_root_cached orig_root, *root = rb_root;
+	struct bpf_rb_node_kern *node;
 	struct rb_node *pos, *n;
 	void *obj;
 
@@ -2303,14 +2304,20 @@ void bpf_rb_root_free(const struct btf_field *field, void *rb_root,
 
 	__bpf_spin_lock_irqsave(spin_lock);
 	orig_root = *root;
+	bpf_rbtree_postorder_for_each_entry_safe(pos, n, &orig_root.rb_root) {
+		node = rb_entry(pos, struct bpf_rb_node_kern, rb_node);
+		WRITE_ONCE(node->owner, BPF_PTR_POISON);
+	}
 	*root = RB_ROOT_CACHED;
 	__bpf_spin_unlock_irqrestore(spin_lock);
 
 	bpf_rbtree_postorder_for_each_entry_safe(pos, n, &orig_root.rb_root) {
 		obj = pos;
 		obj -= field->graph_root.node_offset;
-
-
+		node = rb_entry(pos, struct bpf_rb_node_kern, rb_node);
+		RB_CLEAR_NODE(pos);
+		/* Ensure __bpf_rbtree_add() sees the node as unlinked. */
+		smp_store_release(&node->owner, NULL);
 		__bpf_obj_drop_impl(obj, field->graph_root.value_rec, false);
 	}
 }
@@ -2912,11 +2919,13 @@ __bpf_kfunc struct task_struct *bpf_task_from_vpid(s32 vpid)
 {
 	struct task_struct *p;
 
-	rcu_read_lock();
+	guard(rcu)();
+	if (!task_active_pid_ns(current))
+		return NULL;
+
 	p = find_task_by_vpid(vpid);
 	if (p)
 		p = bpf_task_acquire(p);
-	rcu_read_unlock();
 
 	return p;
 }