From 63b9ab65bd76e5de6479bb14b4014b64aa1a317a Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Fri, 27 Oct 2017 11:05:44 +0800 Subject: [PATCH] tuntap: properly align skb->head before building skb An unaligned alloc_frag->offset caused by previous allocation will result an unaligned skb->head. This will lead unaligned skb_shared_info and then unaligned dataref which requires to be aligned for accessing on some architecture. Fix this by aligning alloc_frag->offset before the frag refilling. Fixes: 0bbd7dad34f8 ("tun: make tun_build_skb() thread safe") Cc: Eric Dumazet Cc: Willem de Bruijn Cc: Wei Wei Cc: Dmitry Vyukov Cc: Mark Rutland Reported-by: Wei Wei Signed-off-by: Jason Wang Signed-off-by: David S. Miller --- drivers/net/tun.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index b9973fb..5550f56 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1286,6 +1286,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun, buflen += SKB_DATA_ALIGN(len + pad); rcu_read_unlock(); + alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL))) return ERR_PTR(-ENOMEM); -- 2.7.4