Date:   Fri, 17 Dec 2021 19:39:54 +1100
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Yang Shen <shenyang39@huawei.com>
Cc:     davem@davemloft.net, linux-kernel@vger.kernel.org,
        linux-crypto@vger.kernel.org, wangzhou1@hisilicon.com,
        liulongfang@huawei.com
Subject: Re: [PATCH] crypto: hisilicon/qm - fix deadlock for remove driver
Message-ID: <20211217083954.GH7018@gondor.apana.org.au>
References: <20211211085655.30294-1-shenyang39@huawei.com>
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On Sat, Dec 11, 2021 at 04:56:55PM +0800, Yang Shen wrote:
> When remove the driver and executing the task occur at the same time,
> the following deadlock will be triggered:
> 
> Chain exists of:
>     sva_lock --> uacce_mutex --> &qm->qps_lock
>     Possible unsafe locking scenario:
> 		CPU0                    CPU1
> 		----                    ----
> 	lock(&qm->qps_lock);
> 					lock(uacce_mutex);
> 					lock(&qm->qps_lock);
> 	lock(sva_lock);
> 
> And the lock 'qps_lock' is used to protect qp. Therefore, it's reasonable
> cycle is to continue until the qp memory is released. So move the release
> lock infront of 'uacce_remove'.
> 
> Signed-off-by: Yang Shen <shenyang39@huawei.com>
> ---
>  drivers/crypto/hisilicon/qm.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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