From: Hugh Dickins <[email protected]> Subject: 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 <[email protected]> Cc: Tejun Heo <[email protected]> Acked-by: Michal Hocko <[email protected]> Cc: Johannes Weiner <[email protected]> Cc: <[email protected]> [3.12+] Signed-off-by: Andrew Morton <[email protected]> --- mm/memcontrol.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff -puN mm/memcontrol.c~mm-memcg-iteration-skip-memcgs-not-yet-fully-initialized mm/memcontrol.c --- a/mm/memcontrol.c~mm-memcg-iteration-skip-memcgs-not-yet-fully-initialized +++ a/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; _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
