Messages in this thread | | | Date | Tue, 31 Aug 2021 12:59:27 -1000 | From | Tejun Heo <> | Subject | Re: [PATCH] kernel/sched: Fix sched_fork() access an invalid sched_task_group |
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Hello,
On Tue, Aug 31, 2021 at 03:58:42PM +0800, Zhang Qiao wrote: > > I think this would allow cgroup migrations to take place before > > sched_post_fork() is run, which likely will break stuff. The right > > thing to do likely is taking sched_task_group (and whatever other > > fields) after cgroup_can_fork(), which fixates the cgroup memberships, > > But it still seems possible that it accessed an invalid sched_task_group? > because the child process does not update its sched_task_group util > cgroup_post_fork().
Between cgroup_can_fork() and cgroup_post_fork(), the cgroup membership and thus sched_task_group can't change, so if the child sets it to the parent's inbetween, the sched_task_group can't go away.
Thanks.
-- tejun
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