Eduard, you are correct, I added some debug output to the kernel itself (in fs/file_table.c) to log the inode number that causes sys_mount to return EBUSY.
The inode in my case was reported as 5669195 which according to the lsof log is exactly the mapping you suspected: plymouthd 3101 0 mem REG 8,5 1 5669195 /root/.cache/dconf/user It seems to be part of d-conf. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1019347 Title: A message: "mount: / is busy" appears every time shutting down or rebooting. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/plymouth/+bug/1019347/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
