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Subject: Re: [PATCH net 1/3] mISDN: hfcsusb: don't call dev_kfree_skb() under
 spin_lock_irqsave()
To:     Jakub Kicinski <kuba@kernel.org>
CC:     <netdev@vger.kernel.org>, <isdn@linux-pingi.de>,
        <davem@davemloft.net>
References: <20221207093239.3775457-1-yangyingliang@huawei.com>
 <20221207093239.3775457-2-yangyingliang@huawei.com>
 <20221209155758.459b858d@kernel.org>
From:   Yang Yingliang <yangyingliang@huawei.com>
Message-ID: <cea4e99a-10f0-c959-c1f2-30fc6614c219@huawei.com>
Date:   Mon, 12 Dec 2022 09:58:03 +0800
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On 2022/12/10 7:57, Jakub Kicinski wrote:
> On Wed, 7 Dec 2022 17:32:37 +0800 Yang Yingliang wrote:
>>   			spin_lock_irqsave(&hw->lock, flags);
>>   			skb_queue_purge(&dch->squeue);
> Please take a look at what skb_queue_purge() does.
> Perhaps you should create a skb_buff_head on the stack,
> skb_queue_splice_init() from the sch->squeue onto that
> queue, add the rx_skb and tx_skb into that queue,
> then drop the lock and skb_queue_purge() outside the lock.
skb_queue_purge() calls kfree_skb() which is not allowed in this
case, I will send a v2 to change it.

Thanks,
Yang
>
>>   			if (dch->tx_skb) {
>> -				dev_kfree_skb(dch->tx_skb);
>> +				dev_consume_skb_irq(dch->tx_skb);
> .