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Commit 8764ab2c authored by Steffen Klassert's avatar Steffen Klassert Committed by David S. Miller
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net: check for refcount if pop a stacked dst_entry 



xfrm triggers a warning if dst_pop() drops a refcount
on a noref dst. This patch changes dst_pop() to
skb_dst_pop(). skb_dst_pop() drops the refcnt only
on a refcounted dst. Also we don't clone the child
dst_entry, so it is not refcounted and we can use
skb_dst_set_noref() in xfrm_output_one().

Signed-off-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 4f4aeb7f

include/net/dst.h

+3 −3
Original line number Diff line number Diff line
@@ -250,11 +250,11 @@ static inline void skb_tunnel_rx(struct sk_buff *skb, struct net_device *dev) 
 * Linux networking.  Thus, destinations are stackable.

 */



static inline struct dst_entry *dst_pop(struct dst_entry *dst)

static inline struct dst_entry *skb_dst_pop(struct sk_buff *skb)

{

	struct dst_entry *child = dst_clone(dst->child);

	struct dst_entry *child = skb_dst(skb)->child;



	dst_release(dst);

	skb_dst_drop(skb);

	return child;

}

net/xfrm/xfrm_output.c

+2 −2
Original line number Diff line number Diff line
@@ -95,13 +95,13 @@ static int xfrm_output_one(struct sk_buff *skb, int err) 
			goto error_nolock;

		}



		dst = dst_pop(dst);

		dst = skb_dst_pop(skb);

		if (!dst) {

			XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);

			err = -EHOSTUNREACH;

			goto error_nolock;

		}

		skb_dst_set(skb, dst);

		skb_dst_set_noref(skb, dst);

		x = dst->xfrm;

	} while (x && !(x->outer_mode->flags & XFRM_MODE_FLAG_TUNNEL));