[PATCH 07/15] net: add debugging checks in skb_attempt_defer_free()

[wen . yang]

From: Eric Dumazet <edumazet@xxxxxxxxxx>

commit e8e1ce8454c9cc8ad2e4422bef346428e52455e3 upstream.

Make sure skbs that are stored in softnet_data.defer_list
do not have a dst attached.

Also make sure the the skb was orphaned.

Link: https://lore.kernel.org/netdev/CANn89iJuEVe72bPmEftyEJHLzzN=QNR2yueFjTxYXCEpS5S8HQ@xxxxxxxxxxxxxx/T/
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Wen Yang <wen.yang@xxxxxxxxx>
---
 net/core/skbuff.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a66066bc9861..919ad5a2c5da 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -6727,6 +6727,9 @@ nodefer:	__kfree_skb(skb);
 		return;
 	}
 
+	DEBUG_NET_WARN_ON_ONCE(skb_dst(skb));
+	DEBUG_NET_WARN_ON_ONCE(skb->destructor);
+
 	sd = &per_cpu(softnet_data, cpu);
 	defer_max = READ_ONCE(sysctl_skb_defer_max);
 	if (READ_ONCE(sd->defer_count) >= defer_max)
-- 
2.25.1