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From:   Weili Qian <qianweili@huawei.com>
To:     <herbert@gondor.apana.org.au>
CC:     <linux-crypto@vger.kernel.org>, <shenyang39@huawei.com>,
        <liulongfang@huawei.com>, Weili Qian <qianweili@huawei.com>
Subject: [PATCH v2 5/7] crypto: hisilicon/qm - prevent soft lockup in qm_poll_req_cb()'s loop
Date:   Fri, 11 Aug 2023 22:07:47 +0800
Message-ID: <20230811140749.5202-6-qianweili@huawei.com>
In-Reply-To: <20230811140749.5202-1-qianweili@huawei.com>
References: <20230811140749.5202-1-qianweili@huawei.com>
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The function qm_poll_req_cb() may take a while due to complex req_cb,
so soft lockup may occur in kernel with preemption disabled.

The error logs:
watchdog: BUG: soft lockup - CPU#23 stuck for 23s! [kworker/u262:1:1407]
[ 1461.978428][   C23] Call trace:
[ 1461.981890][   C23]  complete+0x8c/0xf0
[ 1461.986031][   C23]  kcryptd_async_done+0x154/0x1f4 [dm_crypt]
[ 1461.992154][   C23]  sec_skcipher_callback+0x7c/0xf4 [hisi_sec2]
[ 1461.998446][   C23]  sec_req_cb+0x104/0x1f4 [hisi_sec2]
[ 1462.003950][   C23]  qm_poll_req_cb+0xcc/0x150 [hisi_qm]
[ 1462.009531][   C23]  qm_work_process+0x60/0xc0 [hisi_qm]
[ 1462.015101][   C23]  process_one_work+0x1c4/0x470
[ 1462.020052][   C23]  worker_thread+0x150/0x3c4
[ 1462.024735][   C23]  kthread+0x108/0x13c
[ 1462.028889][   C23]  ret_from_fork+0x10/0x18

Add a cond_resched() to prevent that.

Signed-off-by: Weili Qian <qianweili@huawei.com>
---
 drivers/crypto/hisilicon/qm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
index 376f6a3c5c7f..c9ed30b181bb 100755
--- a/drivers/crypto/hisilicon/qm.c
+++ b/drivers/crypto/hisilicon/qm.c
@@ -958,6 +958,8 @@ static void qm_poll_req_cb(struct hisi_qp *qp)
 		qm_db(qm, qp->qp_id, QM_DOORBELL_CMD_CQ,
 		      qp->qp_status.cq_head, 0);
 		atomic_dec(&qp->qp_status.used);
+
+		cond_resched();
 	}
 
 	/* set c_flag */
-- 
2.33.0