From: Tejun Heo <tj@kernel.org>
To: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: "Michal Koutný" <mkoutny@suse.com>,
"Xuewen Yan" <xuewen.yan94@gmail.com>,
"Imran Khan" <imran.f.khan@oracle.com>,
lizefan.x@bytedance.com, hannes@cmpxchg.org, tglx@linutronix.de,
steven.price@arm.com, peterz@infradead.org,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
"Zhao Gongyi" <zhaogongyi@huawei.com>,
"Zhang Qiao" <zhangqiao22@huawei.com>
Subject: Re: [PATCH cgroup/for-6.0-fixes] cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock
Date: Wed, 17 Aug 2022 07:40:32 -1000 [thread overview]
Message-ID: <Yv0oEOXddKp+Xo1U@slm.duckdns.org> (raw)
In-Reply-To: <YvrWaml3F+x9Dk+T@slm.duckdns.org>
On Mon, Aug 15, 2022 at 01:27:38PM -1000, Tejun Heo wrote:
> Bringing up a CPU may involve creating new tasks which requires read-locking
> threadgroup_rwsem, so threadgroup_rwsem nests inside cpus_read_lock().
> However, cpuset's ->attach(), which may be called with thredagroup_rwsem
> write-locked, also wants to disable CPU hotplug and acquires
> cpus_read_lock(), leading to a deadlock.
>
> Fix it by guaranteeing that ->attach() is always called with CPU hotplug
> disabled and removing cpus_read_lock() call from cpuset_attach().
>
> Signed-off-by: Tejun Heo <tj@kernel.org>
Applied to cgroup/for-6.0-fixes w/ commit message and comment update
suggested by Xuewen and Fixes / stable tags added.
Thanks.
--
tejun
prev parent reply other threads:[~2022-08-17 17:40 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <8245b710-8acb-d8e6-7045-99a5f71dad4e@oracle.com>
2022-07-20 2:38 ` Query regarding deadlock involving cgroup_threadgroup_rwsem and cpu_hotplug_lock Imran Khan
2022-07-20 3:27 ` Imran Khan
2022-07-20 11:06 ` Mukesh Ojha
2022-07-20 12:01 ` Mukesh Ojha
2022-07-20 18:05 ` Tejun Heo
2022-07-27 19:33 ` Tejun Heo
2022-08-12 10:27 ` Mukesh Ojha
2022-08-15 9:05 ` Michal Koutný
2022-08-15 9:25 ` Xuewen Yan
2022-08-15 9:39 ` Michal Koutný
2022-08-15 10:59 ` Mukesh Ojha
2022-08-15 23:27 ` [PATCH cgroup/for-6.0-fixes] cgroup: Fix threadgroup_rwsem <-> cpus_read_lock() deadlock Tejun Heo
2022-08-16 20:20 ` Imran Khan
2022-08-17 6:55 ` Xuewen Yan
2022-08-17 17:40 ` Tejun Heo [this message]
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