From: Jing-Ting Wu Jing-Ting.Wu@mediatek.com
commit 763f4fb76e24959c370cdaa889b2492ba6175580 upstream.
Root cause: The rebind_subsystems() is no lock held when move css object from A list to B list,then let B's head be treated as css node at list_for_each_entry_rcu().
Solution: Add grace period before invalidating the removed rstat_css_node.
Reported-by: Jing-Ting Wu jing-ting.wu@mediatek.com Suggested-by: Michal Koutný mkoutny@suse.com Signed-off-by: Jing-Ting Wu jing-ting.wu@mediatek.com Tested-by: Jing-Ting Wu jing-ting.wu@mediatek.com Link: https://lore.kernel.org/linux-arm-kernel/d8f0bc5e2fb6ed259f9334c83279b4c0112... Acked-by: Mukesh Ojha quic_mojha@quicinc.com Fixes: a7df69b81aac ("cgroup: rstat: support cgroup1") Cc: stable@vger.kernel.org # v5.13+ Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/cgroup/cgroup.c | 1 + 1 file changed, 1 insertion(+)
--- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1810,6 +1810,7 @@ int rebind_subsystems(struct cgroup_root
if (ss->css_rstat_flush) { list_del_rcu(&css->rstat_css_node); + synchronize_rcu(); list_add_rcu(&css->rstat_css_node, &dcgrp->rstat_css_list); }