debug cgroup: use task_css_set instead of rcu_dereference

This macro `task_css_set` verifies that the caller is
inside proper critical section if the kernel set CONFIG_PROVE_RCU=y.

Signed-off-by: Wang Long <wanglong19@meituan.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/cgroup/debug.c b/kernel/cgroup/debug.c
index 5f780d8f6a9d787ed22cf30bd8be66a0ae78f069..9caeda6102491db1a32c34bc62ef75da2cd3f6df 100644 (file)
--- a/kernel/cgroup/debug.c
+++ b/kernel/cgroup/debug.c
@@ -50,7 +50,7 @@ static int current_css_set_read(struct seq_file *seq, void *v)
 
        spin_lock_irq(&css_set_lock);
        rcu_read_lock();
-       cset = rcu_dereference(current->cgroups);
+       cset = task_css_set(current);
        refcnt = refcount_read(&cset->refcount);
        seq_printf(seq, "css_set %pK %d", cset, refcnt);
        if (refcnt > cset->nr_tasks)
@@ -96,7 +96,7 @@ static int current_css_set_cg_links_read(struct seq_file *seq, void *v)
 
        spin_lock_irq(&css_set_lock);
        rcu_read_lock();
-       cset = rcu_dereference(current->cgroups);
+       cset = task_css_set(current);
        list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
                struct cgroup *c = link->cgrp;