Re: [PATCH] isdn: hisax: hfc_pci: Fix a possible concurrency use-after-free bug in HFCPCI_l1hw()

[David Miller]

From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
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@xxxxxxxxx>

Applied.