On 5/2/22 16:26, Jens Axboe wrote:
On 5/2/22 7:17 AM, Daniel Harding wrote:
I use lxc-4.0.12 on Gentoo, built with io-uring support
(--enable-liburing), targeting liburing-2.1. My kernel config is a
very lightly modified version of Fedora's generic kernel config. After
moving from the 5.16.x series to the 5.17.x kernel series, I started
noticed frequent hangs in lxc-stop. It doesn't happen 100% of the
time, but definitely more than 50% of the time. Bisecting narrowed
down the issue to commit aa43477b040251f451db0d844073ac00a8ab66ee:
io_uring: poll rework. Testing indicates the problem is still present
in 5.18-rc5. Unfortunately I do not have the expertise with the
codebases of either lxc or io-uring to try to debug the problem
further on my own, but I can easily apply patches to any of the
involved components (lxc, liburing, kernel) and rebuild for testing or
validation. I am also happy to provide any further information that
would be helpful with reproducing or debugging the problem.
Do you have a recipe to reproduce the hang? That would make it
significantly easier to figure out.
I can reproduce it with just the following:
sudo lxc-create --n lxc-test --template download --bdev dir --dir
/var/lib/lxc/lxc-test/rootfs -- -d ubuntu -r bionic -a amd64
sudo lxc-start -n lxc-test
sudo lxc-stop -n lxc-test
The lxc-stop command never exits and the container continues running.
If that isn't sufficient to reproduce, please let me know.
--
Regards,
Daniel Harding
