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Tejun Heo authored
Currently, there's nothing preventing cgroup_enable_task_cg_lists() from missing set PF_EXITING and race against cgroup_exit(). Depending on the timing, cgroup_exit() may finish with the task still linked on css_set leading to list corruption. Fix it by grabbing siglock in cgroup_enable_task_cg_lists() so that PF_EXITING is guaranteed to be visible. This whole on-demand cg_list optimization is extremely fragile and has ample possibility to lead to bugs which can cause things like once-a-year oops during boot. I'm wondering whether the better approach would be just adding "cgroup_disable=all" handling which disables the whole cgroup rather than tempting fate with this on-demand craziness. Signed-off-by:
Tejun Heo <tj@kernel.org> Acked-by:
Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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