This is *not* a 5.13 kernel issue in Impish. I booted Hirsute with the Impish 5.13.0-14-generic kernel and the cgexec works fine in Hirsute with the 5.13 kernel.
This is *not* a 5.13 kernel issue in Impish. I booted Hirsute with the Impish 5.13.0-14-generic kernel and the cgexec works fine in Hirsute with the 5.13 kernel.