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authorJason Wang <jasowang@redhat.com>2017-10-27 11:05:44 +0800
committerDavid S. Miller <davem@davemloft.net>2017-10-28 19:05:28 +0900
commit63b9ab65bd76e5de6479bb14b4014b64aa1a317a (patch)
tree3822be64ed1349f2d394198b022fe482ddaa47e7
parent8ab190fbe96178449d8195c3582aa10ce684c386 (diff)
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 <edumazet@google.com> Cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com> Cc: Wei Wei <dotweiba@gmail.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Reported-by: Wei Wei <dotweiba@gmail.com> Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/net/tun.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index b9973fb868b7..5550f56cb895 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);