Messages in this thread | | | Date | Mon, 15 Aug 2022 11:05:56 +0200 | From | Michal Koutný <> | Subject | Re: Query regarding deadlock involving cgroup_threadgroup_rwsem and cpu_hotplug_lock |
| |
+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).
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
| |