Re: [PATCH] af_unix: fix holding spinlock in oob handling

On Thu, Aug 12, 2021 at 7:37 PM Shoaib Rao [off-list ref] wrote:

On 8/12/21 12:53 AM, Eric Dumazet wrote:

quoted

         if (ousk->oob_skb)
-               kfree_skb(ousk->oob_skb);
+               consume_skb(ousk->oob_skb);

Should I be using consume_skb(), as the skb is not being consumed, the
ref count is decremented and if zero skb will be freed.

consume_skb() and kfree_skb() have the same ref count handling.

The difference is that kfree_skb() is used by convention when a packet
is dropped

Admins can look closely at packet drops with drop_monitor, or :

perf record -a -g -e skb:kfree_skb sleep 10
perf report

In your case, the oob_skb is not really dropped. It is replaced by
another one, it is part of the normal operation.