4.4-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn willemb@google.com
[ Upstream commit 113f99c3358564a0647d444c2ae34e8b1abfd5b9 ]
Device features may change during transmission. In particular with corking, a device may toggle scatter-gather in between allocating and writing to an skb.
Do not unconditionally assume that !NETIF_F_SG at write time implies that the same held at alloc time and thus the skb has sufficient tailroom.
This issue predates git history.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: Eric Dumazet edumazet@google.com Signed-off-by: Willem de Bruijn willemb@google.com Reviewed-by: Eric Dumazet edumazet@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv4/ip_output.c | 3 ++- net/ipv6/ip6_output.c | 3 ++- 2 files changed, 4 insertions(+), 2 deletions(-)
--- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1062,7 +1062,8 @@ alloc_new_skb: if (copy > length) copy = length;
- if (!(rt->dst.dev->features&NETIF_F_SG)) { + if (!(rt->dst.dev->features&NETIF_F_SG) && + skb_tailroom(skb) >= copy) { unsigned int off;
off = skb->len; --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1529,7 +1529,8 @@ alloc_new_skb: if (copy > length) copy = length;
- if (!(rt->dst.dev->features&NETIF_F_SG)) { + if (!(rt->dst.dev->features&NETIF_F_SG) && + skb_tailroom(skb) >= copy) { unsigned int off;
off = skb->len;