2021-12-11 08:56:10

by Yang Shen

Subject: [PATCH] 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: Yang Shen <[email protected]>
---
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

2021-12-17 08:39:58

by Herbert Xu

Subject: Re: [PATCH] crypto: hisilicon/qm - fix deadlock for remove driver

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 <[email protected]>
> ---
> drivers/crypto/hisilicon/qm.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt