From: Chengfeng Ye <dg573847474@xxxxxxxxx>
[ Upstream commit 56c6be35fcbed54279df0a2c9e60480a61841d6f ]
As &hc->lock is acquired by both timer _hfcpci_softirq() and hardirq
hfcpci_int(), the timer should disable irq before lock acquisition
otherwise deadlock could happen if the timmer is preemtped by the hadr irq.
Possible deadlock scenario:
hfcpci_softirq() (timer)
-> _hfcpci_softirq()
-> spin_lock(&hc->lock);
<irq interruption>
-> hfcpci_int()
-> spin_lock(&hc->lock); (deadlock here)
This flaw was found by an experimental static analysis tool I am developing
for irq-related deadlock.
The tentative patch fixes the potential deadlock by spin_lock_irq()
in timer.
Fixes: b36b654a7e82 ("mISDN: Create /sys/class/mISDN")
Signed-off-by: Chengfeng Ye <dg573847474@xxxxxxxxx>
Link: https://lore.kernel.org/r/20230727085619.7419-1-dg573847474@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/isdn/hardware/mISDN/hfcpci.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
index 41ff2e3dc8430..0a683a66fc612 100644
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -839,7 +839,7 @@ hfcpci_fill_fifo(struct bchannel *bch)
*z1t = cpu_to_le16(new_z1); /* now send data */
if (bch->tx_idx < bch->tx_skb->len)
return;
- dev_kfree_skb(bch->tx_skb);
+ dev_kfree_skb_any(bch->tx_skb);
if (get_next_bframe(bch))
goto next_t_frame;
return;
@@ -895,7 +895,7 @@ hfcpci_fill_fifo(struct bchannel *bch)
}
bz->za[new_f1].z1 = cpu_to_le16(new_z1); /* for next buffer */
bz->f1 = new_f1; /* next frame */
- dev_kfree_skb(bch->tx_skb);
+ dev_kfree_skb_any(bch->tx_skb);
get_next_bframe(bch);
}
@@ -1119,7 +1119,7 @@ tx_birq(struct bchannel *bch)
if (bch->tx_skb && bch->tx_idx < bch->tx_skb->len)
hfcpci_fill_fifo(bch);
else {
- dev_kfree_skb(bch->tx_skb);
+ dev_kfree_skb_any(bch->tx_skb);
if (get_next_bframe(bch))
hfcpci_fill_fifo(bch);
}
@@ -2272,7 +2272,7 @@ _hfcpci_softirq(struct device *dev, void *unused)
return 0;
if (hc->hw.int_m2 & HFCPCI_IRQ_ENABLE) {
- spin_lock(&hc->lock);
+ spin_lock_irq(&hc->lock);
bch = Sel_BCS(hc, hc->hw.bswapped ? 2 : 1);
if (bch && bch->state == ISDN_P_B_RAW) { /* B1 rx&tx */
main_rec_hfcpci(bch);
@@ -2283,7 +2283,7 @@ _hfcpci_softirq(struct device *dev, void *unused)
main_rec_hfcpci(bch);
tx_birq(bch);
}
- spin_unlock(&hc->lock);
+ spin_unlock_irq(&hc->lock);
}
return 0;
}
--
2.40.1
