diff options
| author | Jing-Ting Wu <Jing-Ting.Wu@mediatek.com> | 2022-08-23 08:41:46 +0300 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2022-08-23 21:11:06 +0300 |
| commit | 763f4fb76e24959c370cdaa889b2492ba6175580 (patch) | |
| tree | 541e52a6ef13de29f061d5a3a90eedabb4938e5f | |
| parent | 4f7e7236435ca0abe005c674ebd6892c6e83aeb3 (diff) | |
| download | linux-763f4fb76e24959c370cdaa889b2492ba6175580.tar.xz | |
cgroup: Fix race condition at rebind_subsystems()
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/d8f0bc5e2fb6ed259f9334c83279b4c011283c41.camel@mediatek.com/T/
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>
| -rw-r--r-- | kernel/cgroup/cgroup.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index e1387499b336..e4bb5d57f4d1 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -1820,6 +1820,7 @@ 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); } |