Messages in this thread | | | Date | Tue, 23 Aug 2022 13:03:58 +0530 | Subject | Re: [PATCH 1/1] cgroup: Fix race condition at rebind_subsystems() | From | Mukesh Ojha <> |
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On 8/23/2022 11:11 AM, Jing-Ting Wu wrote: > 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/ > --- > kernel/cgroup/cgroup.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c > index ffaccd6373f1..0d0c959966ed 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); > }
Good catch.
Acked-by: Mukesh Ojha <quic_mojha@quicinc.com>
-Mukesh
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