From 2be27d444f61c5542df5c00892817124582428a4 Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Sun, 15 Jul 2018 21:53:20 +0200 Subject: [PATCH] net: lan78xx: Fix race in tx pending skb size calculation commit dea39aca1d7aef1e2b95b07edeacf04cc8863a2e upstream. The skb size calculation in lan78xx_tx_bh is in race with the start_xmit, which could lead to rare kernel oopses. So protect the whole skb walk with a spin lock. As a benefit we can unlink the skb directly. This patch was tested on Raspberry Pi 3B+ Link: https://github.com/raspberrypi/linux/issues/2608 Fixes: 55d7de9de6c3 ("Microchip's LAN7800 family USB 2/3 to 10/100/1000 Ethernet") Cc: stable Signed-off-by: Floris Bos Signed-off-by: Stefan Wahren Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- drivers/net/usb/lan78xx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/net/usb/lan78xx.c b/drivers/net/usb/lan78xx.c index 9881edc568ba..0aa91ab9a0fb 100644 --- a/drivers/net/usb/lan78xx.c +++ b/drivers/net/usb/lan78xx.c @@ -3197,6 +3197,7 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev) pkt_cnt = 0; count = 0; length = 0; + spin_lock_irqsave(&tqp->lock, flags); for (skb = tqp->next; pkt_cnt < tqp->qlen; skb = skb->next) { if (skb_is_gso(skb)) { if (pkt_cnt) { @@ -3205,7 +3206,8 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev) } count = 1; length = skb->len - TX_OVERHEAD; - skb2 = skb_dequeue(tqp); + __skb_unlink(skb, tqp); + spin_unlock_irqrestore(&tqp->lock, flags); goto gso_skb; } @@ -3214,6 +3216,7 @@ static void lan78xx_tx_bh(struct lan78xx_net *dev) skb_totallen = skb->len + roundup(skb_totallen, sizeof(u32)); pkt_cnt++; } + spin_unlock_irqrestore(&tqp->lock, flags); /* copy to a single skb */ skb = alloc_skb(skb_totallen, GFP_ATOMIC); -- 2.20.1