Messages in this thread | | | From | Xuewen Yan <> | Date | Mon, 15 Aug 2022 17:25:52 +0800 | Subject | Re: Query regarding deadlock involving cgroup_threadgroup_rwsem and cpu_hotplug_lock |
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Hi Michal
On Mon, Aug 15, 2022 at 5:06 PM Michal Koutný <mkoutny@suse.com> wrote: > > +Cc: Zhao Gongyi <zhaogongyi@huawei.com>, Zhang Qiao <zhangqiao22@huawei.com> > > On Fri, Aug 12, 2022 at 03:57:00PM +0530, Mukesh Ojha <quic_mojha@quicinc.com> wrote: > > The original patch of yours [1] and the revert of [2] is fixing the issue > > and it is also confirmed here [3]. > > Can we get proper fix merge on your tree? > > > > [1] https://lore.kernel.org/lkml/YuGbYCfAG81mZBnN@slm.duckdns.org/ > > > > [2] > > https://lore.kernel.org/all/20220121101210.84926-1-zhangqiao22@huawei.com/ > > The revert + Tejun's patch looks fine wrt the problem of the reverted > patch (just moves cpus_read_lock to upper callers).
Your means is that the problem should be fixed by [1]+[2]'s revert ? I just tested the case which reverted the [2]. Need I test with [1] and [2]?
Thanks!
> > I'd just suggest a comment that'd explicitly document also the lock > order that we stick to, IIUC, it should be: > > cpu_hotplug_lock // cpus_read_lock > cgroup_threadgroup_rwsem > cpuset_rwsem > > Michal > > > > > [3] https://lore.kernel.org/lkml/CAB8ipk-72V-bYRfL-VcSRSyXTeQqkBVj+1d5MHSVV5CTar9a0Q@mail.gmail.com/ > > > > -Mukesh
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