[PATCH 4.9 171/251] mISDN: hfcmulti: dont call dev_kfree_skb/kfree_skb() under spin_lock_irqsave()

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From: Yang Yingliang <yangyingliang@xxxxxxxxxx>

[ Upstream commit 1232946cf522b8de9e398828bde325d7c41f29dd ]

It is not allowed to call kfree_skb() or consume_skb() from hardware
interrupt context or with hardware interrupts being disabled.

skb_queue_purge() is called under spin_lock_irqsave() in handle_dmsg()
and hfcm_l1callback(), kfree_skb() is called in them, to fix this, use
skb_queue_splice_init() to move the dch->squeue to a free queue, also
enqueue the tx_skb and rx_skb, at last calling __skb_queue_purge() to
free the SKBs afer unlock.

Fixes: af69fb3a8ffa ("Add mISDN HFC multiport driver")
Signed-off-by: Yang Yingliang <yangyingliang@xxxxxxxxxx>
Reviewed-by: Alexander Duyck <alexanderduyck@xxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/isdn/hardware/mISDN/hfcmulti.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/isdn/hardware/mISDN/hfcmulti.c b/drivers/isdn/hardware/mISDN/hfcmulti.c
index 8feb8e9e29a6..decec530bdf4 100644
--- a/drivers/isdn/hardware/mISDN/hfcmulti.c
+++ b/drivers/isdn/hardware/mISDN/hfcmulti.c
@@ -3234,6 +3234,7 @@ static int
 hfcm_l1callback(struct dchannel *dch, u_int cmd)
 {
 	struct hfc_multi	*hc = dch->hw;
+	struct sk_buff_head	free_queue;
 	u_long	flags;
 
 	switch (cmd) {
@@ -3262,6 +3263,7 @@ hfcm_l1callback(struct dchannel *dch, u_int cmd)
 		l1_event(dch->l1, HW_POWERUP_IND);
 		break;
 	case HW_DEACT_REQ:
+		__skb_queue_head_init(&free_queue);
 		/* start deactivation */
 		spin_lock_irqsave(&hc->lock, flags);
 		if (hc->ctype == HFC_TYPE_E1) {
@@ -3281,20 +3283,21 @@ hfcm_l1callback(struct dchannel *dch, u_int cmd)
 				plxsd_checksync(hc, 0);
 			}
 		}
-		skb_queue_purge(&dch->squeue);
+		skb_queue_splice_init(&dch->squeue, &free_queue);
 		if (dch->tx_skb) {
-			dev_kfree_skb(dch->tx_skb);
+			__skb_queue_tail(&free_queue, dch->tx_skb);
 			dch->tx_skb = NULL;
 		}
 		dch->tx_idx = 0;
 		if (dch->rx_skb) {
-			dev_kfree_skb(dch->rx_skb);
+			__skb_queue_tail(&free_queue, dch->rx_skb);
 			dch->rx_skb = NULL;
 		}
 		test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
 		if (test_and_clear_bit(FLG_BUSY_TIMER, &dch->Flags))
 			del_timer(&dch->timer);
 		spin_unlock_irqrestore(&hc->lock, flags);
+		__skb_queue_purge(&free_queue);
 		break;
 	case HW_POWERUP_REQ:
 		spin_lock_irqsave(&hc->lock, flags);
@@ -3401,6 +3404,9 @@ handle_dmsg(struct mISDNchannel *ch, struct sk_buff *skb)
 	case PH_DEACTIVATE_REQ:
 		test_and_clear_bit(FLG_L2_ACTIVATED, &dch->Flags);
 		if (dch->dev.D.protocol != ISDN_P_TE_S0) {
+			struct sk_buff_head free_queue;
+
+			__skb_queue_head_init(&free_queue);
 			spin_lock_irqsave(&hc->lock, flags);
 			if (debug & DEBUG_HFCMULTI_MSG)
 				printk(KERN_DEBUG
@@ -3422,14 +3428,14 @@ handle_dmsg(struct mISDNchannel *ch, struct sk_buff *skb)
 				/* deactivate */
 				dch->state = 1;
 			}
-			skb_queue_purge(&dch->squeue);
+			skb_queue_splice_init(&dch->squeue, &free_queue);
 			if (dch->tx_skb) {
-				dev_kfree_skb(dch->tx_skb);
+				__skb_queue_tail(&free_queue, dch->tx_skb);
 				dch->tx_skb = NULL;
 			}
 			dch->tx_idx = 0;
 			if (dch->rx_skb) {
-				dev_kfree_skb(dch->rx_skb);
+				__skb_queue_tail(&free_queue, dch->rx_skb);
 				dch->rx_skb = NULL;
 			}
 			test_and_clear_bit(FLG_TX_BUSY, &dch->Flags);
@@ -3441,6 +3447,7 @@ handle_dmsg(struct mISDNchannel *ch, struct sk_buff *skb)
 #endif
 			ret = 0;
 			spin_unlock_irqrestore(&hc->lock, flags);
+			__skb_queue_purge(&free_queue);
 		} else
 			ret = l1_event(dch->l1, hh->prim);
 		break;
-- 
2.35.1






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