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Subject: Re: [PATCH v2] crypto: hisilicon/sec - don't sleep when in softirq
To:     Zhengchao Shao <shaozhengchao@huawei.com>,
        <linux-crypto@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <liulongfang@huawei.com>, <herbert@gondor.apana.org.au>,
        <davem@davemloft.net>
References: <20220630122622.55492-1-shaozhengchao@huawei.com>
CC:     <weiyongjun1@huawei.com>, <yuehaibing@huawei.com>
From:   "yekai(A)" <yekai13@huawei.com>
Message-ID: <4b86ac05-b2e8-56b5-c059-2a4899d347a0@huawei.com>
Date:   Fri, 1 Jul 2022 09:52:39 +0800
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On 2022/6/30 20:26, Zhengchao Shao wrote:
> When kunpeng920 encryption driver is used to deencrypt and decrypt
> packets during the softirq, it is not allowed to use mutex lock. The
> kernel will report the following error:
>
> BUG: scheduling while atomic: swapper/57/0/0x00000300
> Call trace:
> dump_backtrace+0x0/0x1e4
> show_stack+0x20/0x2c
> dump_stack+0xd8/0x140
> __schedule_bug+0x68/0x80
> __schedule+0x728/0x840
> schedule+0x50/0xe0
> schedule_preempt_disabled+0x18/0x24
> __mutex_lock.constprop.0+0x594/0x5dc
> __mutex_lock_slowpath+0x1c/0x30
> mutex_lock+0x50/0x60
> sec_request_init+0x8c/0x1a0 [hisi_sec2]
> sec_process+0x28/0x1ac [hisi_sec2]
> sec_skcipher_crypto+0xf4/0x1d4 [hisi_sec2]
> sec_skcipher_encrypt+0x1c/0x30 [hisi_sec2]
> crypto_skcipher_encrypt+0x2c/0x40
> crypto_authenc_encrypt+0xc8/0xfc [authenc]
> crypto_aead_encrypt+0x2c/0x40
> echainiv_encrypt+0x144/0x1a0 [echainiv]
> crypto_aead_encrypt+0x2c/0x40
> esp_output_tail+0x348/0x5c0 [esp4]
> esp_output+0x120/0x19c [esp4]
> xfrm_output_one+0x25c/0x4d4
> xfrm_output_resume+0x6c/0x1fc
> xfrm_output+0xac/0x3c0
> xfrm4_output+0x64/0x130
> ip_build_and_send_pkt+0x158/0x20c
> tcp_v4_send_synack+0xdc/0x1f0
> tcp_conn_request+0x7d0/0x994
> tcp_v4_conn_request+0x58/0x6c
> tcp_v6_conn_request+0xf0/0x100
> tcp_rcv_state_process+0x1cc/0xd60
> tcp_v4_do_rcv+0x10c/0x250
> tcp_v4_rcv+0xfc4/0x10a4
> ip_protocol_deliver_rcu+0xf4/0x200
> ip_local_deliver_finish+0x58/0x70
> ip_local_deliver+0x68/0x120
> ip_sublist_rcv_finish+0x70/0x94
> ip_list_rcv_finish.constprop.0+0x17c/0x1d0
> ip_sublist_rcv+0x40/0xb0
> ip_list_rcv+0x140/0x1dc
> __netif_receive_skb_list_core+0x154/0x28c
> __netif_receive_skb_list+0x120/0x1a0
> netif_receive_skb_list_internal+0xe4/0x1f0
> napi_complete_done+0x70/0x1f0
> gro_cell_poll+0x9c/0xb0
> napi_poll+0xcc/0x264
> net_rx_action+0xd4/0x21c
> __do_softirq+0x130/0x358
> irq_exit+0x11c/0x13c
> __handle_domain_irq+0x88/0xf0
> gic_handle_irq+0x78/0x2c0
> el1_irq+0xb8/0x140
> arch_cpu_idle+0x18/0x40
> default_idle_call+0x5c/0x1c0
> cpuidle_idle_call+0x174/0x1b0
> do_idle+0xc8/0x160
> cpu_startup_entry+0x30/0x11c
> secondary_start_kernel+0x158/0x1e4
> softirq: huh, entered softirq 3 NET_RX 0000000093774ee4 with
> preempt_count 00000100, exited with fffffe00?
>
> V1: use spin_lock will cause soft lockup
>
> Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>

Reviewed-by: Signed-off-by: Kai Ye <yekai13@huawei.com>

> ---
>  drivers/crypto/hisilicon/sec2/sec.h        |  2 +-
>  drivers/crypto/hisilicon/sec2/sec_crypto.c | 20 ++++++++++----------
>  2 files changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/crypto/hisilicon/sec2/sec.h b/drivers/crypto/hisilicon/sec2/sec.h
> index 42bb486f3b6d..d2a0bc93e752 100644
> --- a/drivers/crypto/hisilicon/sec2/sec.h
> +++ b/drivers/crypto/hisilicon/sec2/sec.h
> @@ -119,7 +119,7 @@ struct sec_qp_ctx {
>  	struct idr req_idr;
>  	struct sec_alg_res res[QM_Q_DEPTH];
>  	struct sec_ctx *ctx;
> -	struct mutex req_lock;
> +	spinlock_t req_lock;
>  	struct list_head backlog;
>  	struct hisi_acc_sgl_pool *c_in_pool;
>  	struct hisi_acc_sgl_pool *c_out_pool;
> diff --git a/drivers/crypto/hisilicon/sec2/sec_crypto.c b/drivers/crypto/hisilicon/sec2/sec_crypto.c
> index 6eebe739893c..71dfa7db6394 100644
> --- a/drivers/crypto/hisilicon/sec2/sec_crypto.c
> +++ b/drivers/crypto/hisilicon/sec2/sec_crypto.c
> @@ -127,11 +127,11 @@ static int sec_alloc_req_id(struct sec_req *req, struct sec_qp_ctx *qp_ctx)
>  {
>  	int req_id;
>
> -	mutex_lock(&qp_ctx->req_lock);
> +	spin_lock_bh(&qp_ctx->req_lock);
>
>  	req_id = idr_alloc_cyclic(&qp_ctx->req_idr, NULL,
>  				  0, QM_Q_DEPTH, GFP_ATOMIC);
> -	mutex_unlock(&qp_ctx->req_lock);
> +	spin_unlock_bh(&qp_ctx->req_lock);
>  	if (unlikely(req_id < 0)) {
>  		dev_err(req->ctx->dev, "alloc req id fail!\n");
>  		return req_id;
> @@ -156,9 +156,9 @@ static void sec_free_req_id(struct sec_req *req)
>  	qp_ctx->req_list[req_id] = NULL;
>  	req->qp_ctx = NULL;
>
> -	mutex_lock(&qp_ctx->req_lock);
> +	spin_lock_bh(&qp_ctx->req_lock);
>  	idr_remove(&qp_ctx->req_idr, req_id);
> -	mutex_unlock(&qp_ctx->req_lock);
> +	spin_unlock_bh(&qp_ctx->req_lock);
>  }
>
>  static u8 pre_parse_finished_bd(struct bd_status *status, void *resp)
> @@ -273,7 +273,7 @@ static int sec_bd_send(struct sec_ctx *ctx, struct sec_req *req)
>  	    !(req->flag & CRYPTO_TFM_REQ_MAY_BACKLOG))
>  		return -EBUSY;
>
> -	mutex_lock(&qp_ctx->req_lock);
> +	spin_lock_bh(&qp_ctx->req_lock);
>  	ret = hisi_qp_send(qp_ctx->qp, &req->sec_sqe);
>
>  	if (ctx->fake_req_limit <=
> @@ -281,10 +281,10 @@ static int sec_bd_send(struct sec_ctx *ctx, struct sec_req *req)
>  		list_add_tail(&req->backlog_head, &qp_ctx->backlog);
>  		atomic64_inc(&ctx->sec->debug.dfx.send_cnt);
>  		atomic64_inc(&ctx->sec->debug.dfx.send_busy_cnt);
> -		mutex_unlock(&qp_ctx->req_lock);
> +		spin_unlock_bh(&qp_ctx->req_lock);
>  		return -EBUSY;
>  	}
> -	mutex_unlock(&qp_ctx->req_lock);
> +	spin_unlock_bh(&qp_ctx->req_lock);
>
>  	if (unlikely(ret == -EBUSY))
>  		return -ENOBUFS;
> @@ -487,7 +487,7 @@ static int sec_create_qp_ctx(struct hisi_qm *qm, struct sec_ctx *ctx,
>
>  	qp->req_cb = sec_req_cb;
>
> -	mutex_init(&qp_ctx->req_lock);
> +	spin_lock_init(&qp_ctx->req_lock);
>  	idr_init(&qp_ctx->req_idr);
>  	INIT_LIST_HEAD(&qp_ctx->backlog);
>
> @@ -1382,7 +1382,7 @@ static struct sec_req *sec_back_req_clear(struct sec_ctx *ctx,
>  {
>  	struct sec_req *backlog_req = NULL;
>
> -	mutex_lock(&qp_ctx->req_lock);
> +	spin_lock_bh(&qp_ctx->req_lock);
>  	if (ctx->fake_req_limit >=
>  	    atomic_read(&qp_ctx->qp->qp_status.used) &&
>  	    !list_empty(&qp_ctx->backlog)) {
> @@ -1390,7 +1390,7 @@ static struct sec_req *sec_back_req_clear(struct sec_ctx *ctx,
>  				typeof(*backlog_req), backlog_head);
>  		list_del(&backlog_req->backlog_head);
>  	}
> -	mutex_unlock(&qp_ctx->req_lock);
> +	spin_unlock_bh(&qp_ctx->req_lock);
>
>  	return backlog_req;
>  }
>