WRITEV with IOSQE_ASYNC broken?

[nick@xxxxxxxxxxxx]

Hi,

I am helping out with the netty io_uring integration, and came across 
some strange behaviour which seems like it might be a bug related to 
async offload of read/write iovecs.

Basically a WRITEV SQE seems to fail reliably with -BADADDRESS when the 
IOSQE_ASYNC flag is set but works fine otherwise (everything else the 
same). This is with 5.9.0-rc3.

Sorry if I've made a mistake somehow, and thanks for all the great work 
on this game-changing feature!

Nick