Comment 6 for bug 1818880

Hi,

As this bug is very hard to trigger, I've been running some tests with qemu
1:2.5+dfsg-5ubuntu10.35 to see if we didn't regress or break anything with the
new patch. My test setup is as follows:

1) Create new QEMU guest with uvt-kvm or virt-install
    # uvt-kvm create xenial release=xenial --cpu 8
2) Install iperf and latest stress-ng from git. Upstream stress-ng is desired to have a consistent load on each guest
    # apt install iperf
    # git clone git://kernel.ubuntu.com/cking/stress-ng
    # cd stress-ng
    # make clean
    # make
3) Start an iperf server instance on the host
    root@host:~# iperf -s
4) Stress the guest instance with the iperf-retry.sh script and stress-ng (run those commands in different screen windows)
    # ./stress-ng --cpu 4 --hdd 4 --io 4 --vm 4
    # ./stress-ng --class network --all 2
    # ./iperf-retry.sh
5) Attach and detach network adapter using the hotplug.sh script
    root@host:~# ./hotplug.sh xenial 52:54:00:19:7a:21

I've tested this with different guests, including Xenial, Bionic and Disco.
Guest instances performed more than ~2000 hotplug cycles each:
    root@host:~# ./hotplug.sh xenial 52:54:00:19:7a:21
    Detach #1
    Interface detached successfully

    Detach #2
    Interface detached successfully

    ...
    Detach #2168
    Interface detached successfully

The QEMU guests work correctly through and after the tests, and it doesn't
look like we ran into any regressions due to the RCU patch.

Thanks,
Heitor