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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yang Shen <shenyang39@huawei.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 0665/1039] crypto: hisilicon/qm - fix deadlock for remove driver
Date:   Mon, 24 Jan 2022 19:40:54 +0100
Message-Id: <20220124184147.732689466@linuxfoundation.org>
In-Reply-To: <20220124184125.121143506@linuxfoundation.org>
References: <20220124184125.121143506@linuxfoundation.org>
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From: Yang Shen <shenyang39@huawei.com>

[ Upstream commit fc6c01f0cd10b89c4b01dd2940e0b0cda1bd82fb ]

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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/hisilicon/qm.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
index 70b0405494db5..1dc6a27ba0e0d 100644
--- a/drivers/crypto/hisilicon/qm.c
+++ b/drivers/crypto/hisilicon/qm.c
@@ -3399,6 +3399,7 @@ void hisi_qm_uninit(struct hisi_qm *qm)
 		dma_free_coherent(dev, qm->qdma.size,
 				  qm->qdma.va, qm->qdma.dma);
 	}
+	up_write(&qm->qps_lock);
 
 	qm_irq_unregister(qm);
 	hisi_qm_pci_uninit(qm);
@@ -3406,8 +3407,6 @@ void hisi_qm_uninit(struct hisi_qm *qm)
 		uacce_remove(qm->uacce);
 		qm->uacce = NULL;
 	}
-
-	up_write(&qm->qps_lock);
 }
 EXPORT_SYMBOL_GPL(hisi_qm_uninit);
 
-- 
2.34.1