Comment 16 for bug 1718397

Verification done on Xenial v4.4-based kernel.

$ lsb_release -d
Description: Ubuntu 16.04.3 LTS

$ wget 'https://launchpadlibrarian.net/337656213/file_146489.txt' -O io_setup_v2.c
$ sudo apt-get install gcc libaio-dev
$ gcc -o io_setup_v2 io_setup_v2.c -laio

Previous kernel:
---------------

$ sudo apt-get --yes install linux-image-generic=4.4.0.97.102
$ sudo kexec --append="$(cat /proc/cmdline)" --initrd=/boot/initrd.img-4.4.0-97-generic /boot/vmlinux-4.4.0-97-generic
...
$ uname -rv
4.4.0-97-generic #120-Ubuntu SMP Tue Sep 19 17:26:02 UTC 2017

$ ./io_setup_v2 1 65536
nr_events: 1, nr_requests: 65536
rc = -11, i = 409
^Z
[1]+ Stopped ./io_setup_v2 1 65536
$ cat /proc/sys/fs/aio-nr
130880
$ cat /proc/sys/fs/aio-max-nr
65536
$ kill %%

Current kernel:
--------------

$ sudo apt-get --yes install linux-image-generic=4.4.0.98.103
$ sudo kexec --append="$(cat /proc/cmdline)" --initrd=/boot/initrd.img-4.4.0-98-generic /boot/vmlinux-4.4.0-98-generic
...
$ uname -rv
4.4.0-98-generic #121-Ubuntu SMP Tue Oct 10 14:23:01 UTC 2017

$ ./io_setup_v2 1 65536
nr_events: 1, nr_requests: 65536
rc = -12, i = 65515
^Z
[1]+ Stopped ./io_setup_v2 1 65536

$ cat /proc/sys/fs/aio-nr
65515

$ cat /proc/sys/fs/aio-max-nr
65536