[gentoo-user] strange behaviour in quite special case

[Francisco Ares <frares@gmail.com>]

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Hi, All.

This is a rather special case, so I don't expect much, but who knows?

I've built a Gentoo x86-64 system for an embedded application.

Just after a lot of updates, which I am unable to track, it stopped working
as usual.

There is the development system, fully loaded of a lot of packages used for
development, and the production system, that don't need all of those.

There is a line in both systems in /etc/iniitab responsible for auto-login
the production system user and the programs we need running (in its
".bash_profile" and ".xinitrc"):

c6:2345:respawn:/sbin/agetty -a production-user 38400 tty6 linux

The development system starts a WindowMaker session, and the production
system starts a program that controls the rest of the hardware of this
embedded system, with an X11 graphical interface.  That runs normally when
simulated at the development system.

The development system runs smoothly.  The production system, after
removing the files from undesirable packages and creating a squashfs image
of the ripped-off root partition behaves strangely at boot:

It shows the initialization messages as expected, but when the auto-login
and the controller program start should take place, it completely stalls up
to I plug a USB keyboard and issue some times some of the key combinations
to change to a text console and back to X11 (Ctrl-Alt-F1 and Ctrl-Alt-F6);
 only then the things resume as expected.

As you might suspect, there is no keyboard for the production system ;-) .

As a matter of fact, I don't know where the stall take place, as when I try
to switch to a text console to see the logs, it switches back to X11 and
starts our program.  By the way, the logs just show that the events
occurred at latter times than expected.

Although the squashfs is read-only, some main directories are arranged in a
way that, using tmpfs mounts and unionfs with the read-only directory to
the read-write tmpfs directory to that main directory provide a way of
creating temporary files that has been working for a few years now.

For instance, in "/etc/fstab":

tmpfs           /.etc.rw        tmpfs           defaults,mode=755
                                        0 0
union           /etc            unionfs
        default_permissions,allow_other,use_ino,nonempty,suid,cow,dirs=/.
etc.rw=rw:/.etc.ro=ro          0 0

And there is a "/.etc.ro" with a copy of all files present in regular
"/etc" , a "/.etc.rw" directory to be mounted tmpfs, and the original
"/etc" directory, that needs to be there at boot, even before mounting all
this.

Does anyone have a clue?

Thanks!
Francisco

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