cgroup: allow NULL return from ss->css_alloc()

cgroup core expected css_alloc to return an ERR_PTR value on failure
and caused NULL deref if it returned NULL.  It's an easy mistake to
make from an alloc function and there's no ambiguity in what's being
indicated.  Update css_create() so that it interprets NULL return from
css_alloc as -ENOMEM.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2016-06-21 13:06:24 -04:00
parent d6ccc55e66
commit e7e15b87f8

View File

@ -5133,6 +5133,8 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
lockdep_assert_held(&cgroup_mutex);
css = ss->css_alloc(parent_css);
if (!css)
css = ERR_PTR(-ENOMEM);
if (IS_ERR(css))
return css;