Udp packet drops and packet receive error difference

You are a master!!

I have been suffering from the same problem (this case with a tg3 driver).
The software (composed by several pieces) run ok but after 6 hours one these pieces start to work weirdly, just the one in charge of processing UDP packages (about 6 MBytes/second) and even though, NTP daemon started to make strange things (WTF).
I run dropwatch and realised that I got the same “drops at udp_queue_rcv_skb” messages as you.
After reducing the rcv buffer to 2 MB all problems went away.

Thank you friend!