From:   Yang Shen <shenyang39@huawei.com>
To:     <herbert@gondor.apana.org.au>, <davem@davemloft.net>
CC:     <linux-kernel@vger.kernel.org>, <linux-crypto@vger.kernel.org>,
        <wangzhou1@hisilicon.com>, <liulongfang@huawei.com>
Subject: [PATCH] crypto: hisilicon/qm - fix deadlock for remove driver
Date:   Sat, 11 Dec 2021 16:56:55 +0800
Message-ID: <20211211085655.30294-1-shenyang39@huawei.com>
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Precedence: bulk

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(-)

diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
index 896255aec87f..bea8622d80e6 100644
--- a/drivers/crypto/hisilicon/qm.c
+++ b/drivers/crypto/hisilicon/qm.c
@@ -3425,6 +3425,7 @@ 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);
@@ -3432,8 +3433,6 @@ 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);

--
2.33.0