Commit fc6c01f0 authored by Yang Shen's avatar Yang Shen Committed by Herbert Xu
Browse files

crypto: hisilicon/qm - fix deadlock for remove driver 



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: default avatarYang Shen <shenyang39@huawei.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 808957ba

drivers/crypto/hisilicon/qm.c

+1 −2
Original line number Diff line number Diff line
@@ -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);