From: Jing-Ting Wu <Jing-Ting.Wu@mediatek.com> mainline inclusion from mainline-v6.0-rc3 commit 763f4fb76e24959c370cdaa889b2492ba6175580 category: bugfix bugzilla: 187794, https://gitee.com/openeuler/kernel/issues/I5ZXVK CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------- 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: Cai Xinchen <caixinchen1@huawei.com> Reviewed-by: GONG Ruiqi <gongruiqi1@huawei.com> Reviewed-by: Wang Weiyang <wangweiyang2@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- kernel/cgroup/cgroup.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 57f4e19df8c6..46d5c120c626 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1781,6 +1781,7 @@ int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask) 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); } -- 2.20.1