[systemd-devel] In what case will debugfs be mounted multi-times?

[Lennart Poettering]

On Thu, 04.06.15 23:41, cee1 (fykcee1 at gmail.com) wrote:

> Hi all,
> 
> I'm running systemd v219 on a ARM board, and find following suspicious
> log message:
> """
> Jan 01 08:00:01 localhost unknown: c3 1 (systemd) systemd[1]: Mounting
> Debug File System...
> 
> Jan 01 08:00:01 localhost unknown: c3 1 (systemd) systemd[1]: Starting
> Remount Root and Kernel File Systems...
> 
> Jan 01 08:00:01 localhost unknown: c3 1 (systemd) systemd[1]: Starting
> Foo Service...
> 
> Jan 01 08:00:01 localhost unknown: c3 1 (systemd) systemd[1]: Mounted
> Debug File System.
> 
> Jan 01 08:00:01 localhost systemd[1]: foo.service: main process
> exited, code=exited, status=127/n/a
> 
> Jan 01 08:00:02 localhost systemd[1]: foo.service holdoff time over,
> scheduling restart.
> 
> Jan 01 08:00:02 localhost systemd[1]: Started Remount Root and Kernel
> File Systems.
> 
> Jan 01 08:00:02 localhost systemd[1]: Reached target Local File Systems (Pre).
> 
> Jan 01 08:00:02 localhost systemd[1]: Starting Local File Systems (Pre).
> 
> Jan 01 08:00:02 localhost systemd[1]: sys-kernel-debug.mount:
> Directory /sys/kernel/debug to mount over is not empty, mounting
> anyway.
> 
> Jan 01 08:00:02 localhost systemd[1]: Mounting Debug File System...
> 
> Jan 01 08:00:02 localhost systemd[1]: sys-kernel-debug.mount mount
> process exited, code=exited status=32
> 
> Jan 01 08:00:02 localhost systemd[1]: Failed to mount Debug File System.
> """
> 
> 
> foo.service is a service with DefaultDependencies=no and Conflicts and
> Before shutdown.target
> 
> So why the Debug File System is mounted multi-times here? Any idea?

Hmm, my suspicion is that the file system might actually already be
mounted by the kernel the second time we look at it, but systemd is
doesn't notice that or so.

Is it possible that your kernel has been built without
name_to_handle_at() or so?

Lennart

-- 
Lennart Poettering, Red Hat