While reviewing AIO code, we found an issue with AioCtlShmemSize function. The function was not accounting for io_handles which is used post shared memory alloc in AioShmemInit. Please find a patch to account for io_handles member of PgAioCtl.
The patch uses sizeof(PgAioCtl) instead of offsetof(PgAioCtl, io_handles) in AioCtlShmemSize.