kernel/include/trace/events/udp.h, branch linux-3.11.y Hosts the 0x221E linux distro kernel. https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-3.11.y 2011-06-21T23:06:10Z udp: add tracepoints for queueing skb to rcvbuf 2011-06-21T23:06:10Z Satoru Moriya satoru.moriya@hds.com 2011-06-17T11:58:39Z urn:sha1:296f7ea75b45913d5e2067baef0812087e0b6eb9 This patch adds a tracepoint to __udp_queue_rcv_skb to get the return value of ip_queue_rcv_skb. It indicates why kernel drops a packet at this point. ip_queue_rcv_skb returns following values in the packet drop case: rcvbuf is full : -ENOMEM sk_filter returns error : -EINVAL, -EACCESS, -ENOMEM, etc. __sk_mem_schedule returns error: -ENOBUF Signed-off-by: Satoru Moriya <satoru.moriya@hds.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>