On Tue, 2017-07-25 at 13:57 +0200, Marc Haber wrote: > On Mon, Jul 24, 2017 at 04:19:10PM +0200, Paolo Abeni wrote: > > Once that a system enter the buggy status, do the packets reach the > > relevant socket's queue? > > > > ss -u > > That one only shows table headers on an unaffected system in normal > operation, right?
This one shows the current lenght of the socket receive queue (Recv-Q, the first column). If the packets land into the skbuff (and the user space reader for some reason is not woken up) such value will grow over time. > > nstat |grep -e Udp -e Ip > > > > will help checking that. > > An unaffected system will show UdpInDatagrams, right? > > But where is the connection to the relevant socket's queue? If the socket queue lenght (as reported above) does not increase, IP/UDP stats could give an hint of where and why the packets stop traversing the network stack. Beyond that, you can try using perf probes or kprobe/systemtap to [try to] track the relevant packets inside the kernel. /P
