I was logged in using ssh. I did an
ethconfig eth0 mtu 9000
that being the usual built-in wired ethernet, was all good,
ping -s 4000 some_global_ipv4_address
and that either stuffed my ssh session, or killed the o/s, hung the process, I can't tell which, I couldn't recover from it anyway. I don't have a screen or keyboard. I power-cycled the pi to recover.
Could someone try reproducing this perhaps? - but on a non-headless system too. Which I physically can't do (due to disability - long story skipped - see my earlier posts).
And would someone be kind enough to report this as a bug in <x> as you think appropriate as I am not able to do so myself.
Pings of size 1800 (and ~2000 too iirc) were ok. It's not that there is a limit around 1500 anyway.
For what it's worth:
The ping was directed to a box in my own Lan. The eth0 interface was using a global routable IPv4 address assigned by dhcp and also various global routable ipv6 address obtained from prefix ra from my router as I have an ipv6 isp and a global /48. The ethernet i/f also had additional static IPv4 addresses as well assigned to eth0:0 eth0:1 these being in the 10.0.0.0/8 and 169.254.*.* ranges plus a link-local ipv6 address.
Keywords long ping jumbo frames raspbian jessie ping -s