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authorHugh Dickins <hughd@google.com>2014-01-23 15:53:32 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-01-23 16:36:53 -0800
commitd8ad30559715ce97afb7d1a93a12fd90e8fff312 (patch)
treede34c8716415741701e60981b89cfeb2aef114da /mm
parentd2ab70aaae74456ed608740915dc82ef52291f69 (diff)
downloadlinux-next-d8ad30559715ce97afb7d1a93a12fd90e8fff312.tar.gz
mm/memcg: iteration skip memcgs not yet fully initialized
It is surprising that the mem_cgroup iterator can return memcgs which have not yet been fully initialized. By accident (or trial and error?) this appears not to present an actual problem; but it may be better to prevent such surprises, by skipping memcgs not yet online. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> [3.12+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index aa66cc4c9e79..9537e1389ee6 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1119,10 +1119,8 @@ skip_node:
* protected by css_get and the tree walk is rcu safe.
*/
if (next_css) {
- struct mem_cgroup *mem = mem_cgroup_from_css(next_css);
-
- if (css_tryget(&mem->css))
- return mem;
+ if ((next_css->flags & CSS_ONLINE) && css_tryget(next_css))
+ return mem_cgroup_from_css(next_css);
else {
prev_css = next_css;
goto skip_node;