[PATCH net-next] net: add a temporary sanity check in skb_orphan()

[PATCH net-next] net: add a temporary sanity check in skb_orphan()

[Eric Dumazet]

From: Eric Dumazet <edumazet@google.com>

David suggested to add a BUG_ON() to catch if some layer
sets skb->sk pointer without a corresponding destructor.

As skb can sit in a queue, it's mandatory to make sure the
socket cannot disappear, and it's usually done by taking a
reference on the socket, then releasing it from the skb
destructor.

This patch is a follow-up to commit c34a761231b5
("net: skb_orphan() changes") and will be reverted after
catching all possible offenders if any.

Suggested-by: David Miller <davem@davemloft.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/linux/skbuff.h |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index a95547a..d48de68 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1809,6 +1809,8 @@ static inline void skb_orphan(struct sk_buff *skb)
 		skb->destructor(skb);
 		skb->destructor = NULL;
 		skb->sk		= NULL;
+	} else {
+		BUG_ON(skb->sk);
 	}
 }
 

Re: [PATCH net-next] net: add a temporary sanity check in skb_orphan()

[David Miller]

From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 01 Aug 2013 11:43:08 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> David suggested to add a BUG_ON() to catch if some layer
> sets skb->sk pointer without a corresponding destructor.
> 
> As skb can sit in a queue, it's mandatory to make sure the
> socket cannot disappear, and it's usually done by taking a
> reference on the socket, then releasing it from the skb
> destructor.
> 
> This patch is a follow-up to commit c34a761231b5
> ("net: skb_orphan() changes") and will be reverted after
> catching all possible offenders if any.
> 
> Suggested-by: David Miller <davem@davemloft.net>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Applied, thanks Eric.