Comment # 6 on bug 911435 from Miklos Szeredi

I'm not familiar with docker.

Is there an another "docker" process running?  Because this strace doesn't have
any mount or umount syscalls (the Oops was triggered by umount()).

If there's a "docker" daemon, could you please attach strace to it with:

strace -p PID_OF_DOCKER -f -o /tmp/strace

Thanks.