Created attachment 849953 [details]
lxc-start backtrace

Hello Everyone,
After upgrading from snapshot 20210527 to 20210601, lxc-attach isn't working
anymore for unprivileged lxc-containers.

When I start the container with lxc-start -F, and run lxc-attach in another
window, lxc-attach returns silently, the window with lxc-start says
"Segmentation fault (core dumped)" and the container is in stopped state
afterwards. This only happens with unprivileged lxc containers. Normal
containers seem to work fine.

A backtrace is attached.