tree 732d18013dc3e3eb26f1c5d2b9b9c9d541b8ed1c
parent f9fc54d313fab2834f44f516459cdc8ac91d797f
author Jia-Ju Bai <baijiaju1990@gmail.com> 1545833374 +0800
committer David S. Miller <davem@davemloft.net> 1546061251 -0800

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

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>
Signed-off-by: David S. Miller <davem@davemloft.net>