From 88dccf5b344163645d694d74cffc5a7e64a385bb Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Fri, 3 May 2013 04:22:04 +0000 Subject: [PATCH] sky2: Fix crash on receiving VLAN frames After recent 86a9bad3 (net: vlan: add protocol argument to packet tagging functions) my sky2 started to crash on receive of tagged frames, with backtrace similar to #CRASH!!! vlan_do_receive __netif_receive_skb_core __netif_receive_skb netif_receive_skb sky2_poll ... __net_rx_action __do_softirq The problem turned out to be: 1) sky2 copies small packets from ring on RX, and in its receive_copy() skb header is copied manually field, by field, and only for some fields; 2) 86a9bad3 added skb->vlan_proto, which vlan_untag() or __vlan_hwaccel_put_tag() set, and which is later used in vlan_do_receive(). That patch updated copy_skb_header() for newly introduced skb->vlan_proto, but overlooked the need to also copy it in sky2's receive_copy(). Because of 2, we have the following scenario: - frame is received and tagged in a ring, by sky2_rx_tag(). Both skb->vlan_proto and skb->vlan_tci are set; - later skb is decided to be copied, but skb->vlan_proto is forgotten and becomes 0. - in the beginning of vlan_do_receive() we call __be16 vlan_proto = skb->vlan_proto; vlan_dev = vlan_find_dev(skb->dev, vlan_proto, vlan_id); which eventually invokes vlan_proto_idx(vlan_proto) and that routine BUGs for everything except ETH_P_8021Q and ETH_P_8021AD. Oops. Fix it. P.S. Stephen, I wonder, why copy_skb_header() is not used in sky2.c::receive_copy() ? Problems, where receive_copy was updated field by field showed several times already, e.g. 3f42941b (sky2: propogate rx hash when packet is copied) e072b3fa (sky2: fix receive length error in mixed non-VLAN/VLAN traffic) Cc: Patrick McHardy Cc: Stephen Hemminger Cc: Mirko Lindner Signed-off-by: Kirill Smelkov Acked-by: Stephen Hemminger Signed-off-by: David S. Miller --- drivers/net/ethernet/marvell/sky2.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/ethernet/marvell/sky2.c b/drivers/net/ethernet/marvell/sky2.c index 256ae789c143..d175bbd3ffd3 100644 --- a/drivers/net/ethernet/marvell/sky2.c +++ b/drivers/net/ethernet/marvell/sky2.c @@ -2496,10 +2496,12 @@ static struct sk_buff *receive_copy(struct sky2_port *sky2, skb->ip_summed = re->skb->ip_summed; skb->csum = re->skb->csum; skb->rxhash = re->skb->rxhash; + skb->vlan_proto = re->skb->vlan_proto; skb->vlan_tci = re->skb->vlan_tci; pci_dma_sync_single_for_device(sky2->hw->pdev, re->data_addr, length, PCI_DMA_FROMDEVICE); + re->skb->vlan_proto = 0; re->skb->vlan_tci = 0; re->skb->rxhash = 0; re->skb->ip_summed = CHECKSUM_NONE; -- 2.11.0