From: Tejun Heo <tj@kernel.org>
To: Waiman Long <longman@redhat.com>
Cc: Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
Phil Auld <pauld@redhat.com>
Subject: Re: [PATCH] cgroup/cpuset: Fix "suspicious RCU usage" lockdep warning
Date: Thu, 3 Feb 2022 06:06:24 -1000 [thread overview]
Message-ID: <Yfv9gBps4FU7QgLz@slm.duckdns.org> (raw)
In-Reply-To: <20220203033103.773030-1-longman@redhat.com>
On Wed, Feb 02, 2022 at 10:31:03PM -0500, Waiman Long wrote:
> It was found that a "suspicious RCU usage" lockdep warning was issued
> with the rcu_read_lock() call in update_sibling_cpumasks(). It is
> because the update_cpumasks_hier() function may sleep. So we have
> to release the RCU lock, call update_cpumasks_hier() and reacquire
> it afterward.
>
> Also add a percpu_rwsem_assert_held() in update_sibling_cpumasks()
> instead of stating that in the comment.
>
> Fixes: 4716909cc5c5 ("cpuset: Track cpusets that use parent's effective_cpus")
> Signed-off-by: Waiman Long <longman@redhat.com>
Applied to cgroup/for-5.17-fixes.
Thanks.
--
tejun
prev parent reply other threads:[~2022-02-03 16:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-03 3:31 Waiman Long
2022-02-03 15:23 ` Phil Auld
2022-02-03 16:06 ` Tejun Heo [this message]
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