Commit 22296a5c authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: add debug info to __skb_pull() 



While analyzing yet another syzbot report, I found the following
patch very useful. It allows to better understand what went wrong.

This debug info is only enabled if CONFIG_DEBUG_NET=y,
which is the case for syzbot builds.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Acked-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent eb0b39ef

include/linux/skbuff.h

+8 −1
Original line number Diff line number Diff line
@@ -2696,7 +2696,14 @@ void *skb_pull(struct sk_buff *skb, unsigned int len); 
static inline void *__skb_pull(struct sk_buff *skb, unsigned int len)

{

	skb->len -= len;

	BUG_ON(skb->len < skb->data_len);

	if (unlikely(skb->len < skb->data_len)) {

#if defined(CONFIG_DEBUG_NET)

		skb->len += len;

		pr_err("__skb_pull(len=%u)\n", len);

		skb_dump(KERN_ERR, skb, false);

#endif

		BUG();

	}

	return skb->data += len;

}