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Date:   Fri, 28 Dec 2018 21:27:51 -0800 (PST)
Message-Id: <20181228.212751.1498034981468762216.davem@davemloft.net>
To:     baijiaju1990@gmail.com
Cc:     isdn@linux-pingi.de, natechancellor@gmail.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] isdn: hisax: hfc_pci: Fix a possible concurrency
 use-after-free bug in HFCPCI_l1hw()
From:   David Miller <davem@davemloft.net>
In-Reply-To: <20181226140934.12903-1-baijiaju1990@gmail.com>
References: <20181226140934.12903-1-baijiaju1990@gmail.com>
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From: Jia-Ju Bai <baijiaju1990@gmail.com>
Date: Wed, 26 Dec 2018 22:09:34 +0800

> In drivers/isdn/hisax/hfc_pci.c, the functions hfcpci_interrupt() and
> HFCPCI_l1hw() may be concurrently executed.
> 
> HFCPCI_l1hw()
>   line 1173: if (!cs->tx_skb)
> 
> hfcpci_interrupt()
>   line 942: spin_lock_irqsave();
>   line 1066: dev_kfree_skb_irq(cs->tx_skb);
> 
> Thus, a possible concurrency use-after-free bug may occur 
> in HFCPCI_l1hw().
> 
> To fix these bugs, the calls to spin_lock_irqsave() and
> spin_unlock_irqrestore() are added in HFCPCI_l1hw(), to protect the
> access to cs->tx_skb.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>

Applied.