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From:   Ping-Ke Shih <pkshih@realtek.com>
To:     Yang Yingliang <yangyingliang@huawei.com>,
        "Jes.Sorensen@gmail.com" <Jes.Sorensen@gmail.com>,
        "kvalo@kernel.org" <kvalo@kernel.org>
CC:     "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: RE: [PATCH v2] wifi: rtl8xxxu: don't call dev_kfree_skb() under spin_lock_irqsave()
Thread-Topic: [PATCH v2] wifi: rtl8xxxu: don't call dev_kfree_skb() under
 spin_lock_irqsave()
Thread-Index: AQHZCxKwiLtwYwwQM0aow2sFSS4mC65k5qhQ
Date:   Fri, 9 Dec 2022 03:29:24 +0000
Message-ID: <bb02b109787c467494c3886a90b16b95@realtek.com>
References: <20221208143517.2383424-1-yangyingliang@huawei.com>
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> -----Original Message-----
> From: Yang Yingliang <yangyingliang@huawei.com>
> Sent: Thursday, December 8, 2022 10:35 PM
> To: Jes.Sorensen@gmail.com; kvalo@kernel.org; Ping-Ke Shih <pkshih@realtek.com>
> Cc: linux-wireless@vger.kernel.org; yangyingliang@huawei.com
> Subject: [PATCH v2] wifi: rtl8xxxu: don't call dev_kfree_skb() under spin_lock_irqsave()
> 
> It is not allowed to call kfree_skb() or consume_skb() from hardware
> interrupt context or with hardware interrupts being disabled.
> 
> It should use dev_kfree_skb_irq() or dev_consume_skb_irq() instead.
> The difference between them is free reason, dev_kfree_skb_irq() means
> the SKB is dropped in error and dev_consume_skb_irq() means the SKB
> is consumed in normal.
> 
> In this case, dev_kfree_skb() is called to free and drop the SKB when
> it's shutdown, so replace it with dev_kfree_skb_irq(). Compile tested
> only.
> 
> Fixes: 26f1fad29ad9 ("New driver: rtl8xxxu (mac80211)")
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>

Reviewed-by: Ping-Ke Shih <pkshih@realtek.com>

> ---
> v1 -> v2:
>   Update commit message, and change to use dev_kfree_skb_irq().
> ---
>  drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> index ac641a56efb0..d0600af5bef4 100644
> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> @@ -5274,7 +5274,7 @@ static void rtl8xxxu_queue_rx_urb(struct rtl8xxxu_priv *priv,
>  		pending = priv->rx_urb_pending_count;
>  	} else {
>  		skb = (struct sk_buff *)rx_urb->urb.context;
> -		dev_kfree_skb(skb);
> +		dev_kfree_skb_irq(skb);
>  		usb_free_urb(&rx_urb->urb);
>  	}
> 
> --
> 2.25.1
> 
> 
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