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Date: Thu, 4 Jan 2024 08:37:28 -0400
From: Jason Gunthorpe <jgg@ziepe.ca>
To: Shifeng Li <lishifeng@sangfor.com.cn>
Cc: leon@kernel.org, wenglianfa@huawei.com, gustavoars@kernel.org,
	linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org,
	Shifeng Li <lishifeng1992@126.com>,
	"Ding, Hui" <dinghui@sangfor.com.cn>
Subject: Re: [PATCH] RDMA/device: Fix a race between mad_client and cm_client
 init
Message-ID: <20240104123728.GC50608@ziepe.ca>
References: <20240102034335.34842-1-lishifeng@sangfor.com.cn>
 <20240103184804.GB50608@ziepe.ca>
 <80cac9fd-7fed-403e-8889-78e2fc7a49b0@sangfor.com.cn>
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On Thu, Jan 04, 2024 at 02:48:14PM +0800, Shifeng Li wrote:

> The root cause is that mad_client and cm_client may init concurrently
> when devices_rwsem write semaphore is downgraded in enable_device_and_get() like:

That can't be true, the module loader infrastructue ensures those two
things are sequential.

You are trying to say that the post-client fixup stuff will still see
the DEVICE_REGISTERED before it reaches the clients_rwsem lock?

That probably just says the clients_rwsem should be obtained before
changing the DEVICE_STATE too :\

Jason