In drivers/isdn/hisax/hfc_2bds0.c, the function hfc2bds0_interrupt() and HFCD_l1hw() may be concurrently executed.
HFCD_l1hw() line 969: if (!cs->tx_skb) hfc2bds0_interrupt() line 875: dev_kfree_skb_irq(cs->tx_skb); Thus, a possible concurrency use-after-free bug may occur in HFCD_l1hw(). To fix these bugs, the calls to spin_lock_irqsave() and spin_unlock_irqrestore() are added in HFCD_l1hw(), to protect the access to cs->tx_skb. See commit 7418e6520f22 ("isdn: hisax: hfc_pci: Fix a possible concurrency use-after-free bug in HFCPCI_l1hw()") for details. Signed-off-by: Young Xiao <92siuy...@gmail.com> --- drivers/isdn/hisax/hfc_2bds0.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/isdn/hisax/hfc_2bds0.c b/drivers/isdn/hisax/hfc_2bds0.c index 3715fa0..ade12c0 100644 --- a/drivers/isdn/hisax/hfc_2bds0.c +++ b/drivers/isdn/hisax/hfc_2bds0.c @@ -966,11 +966,13 @@ HFCD_l1hw(struct PStack *st, int pr, void *arg) if (cs->debug & L1_DEB_LAPD) debugl1(cs, "-> PH_REQUEST_PULL"); #endif + spin_lock_irqsave(&cs->lock, flags); if (!cs->tx_skb) { test_and_clear_bit(FLG_L1_PULL_REQ, &st->l1.Flags); st->l1.l1l2(st, PH_PULL | CONFIRM, NULL); } else test_and_set_bit(FLG_L1_PULL_REQ, &st->l1.Flags); + spin_unlock_irqrestore(&cs->lock, flags); break; case (HW_RESET | REQUEST): spin_lock_irqsave(&cs->lock, flags); -- 2.7.4