Fwd: Re: After exiting weston all consoles not working anymore

[Thilo Cestonaro]

Further debugging.

I managed to start weston-launch from tty1 without --tty, --user and 
openvt as a normal user.

While weston is running I can switch between tty1-6 with Ctrl+Alt+FX.
When I stop weston (Ctrl+Alt+Backspace), the display gets black and 
switching the consoles isn't possible anymore.

It looks like weston-launch recieves a SIGSEGV. At least gdb tells this.
Sadly I cant get any bt as the "program no longer exists" :(

GDBServer outputs:
Child terminated with signal = 0xb (SIGSEGV)

BUT, the script which I start weston-launch from (which holds only one 
line which is the launch of weston-launch)
is still running.... fork .... while(1) ?

Any ideas how I can debug this?

Cheers,

Thilo


-------- Originalnachricht --------
Betreff: Re: After exiting weston all consoles not working anymore
Datum: 19.03.2015 14:00
Von: Thilo Cestonaro <thilo at cestona.ro>
An: Pekka Paalanen <ppaalanen at gmail.com>
Kopie: wayland-devel at lists.freedesktop.org

>> 
>> > Is anything actually switching to vt7? I'm not sure what weston-launch
>> > does there, usually it takes the current VT and you don't seem to be
>> > telling openvt to switch.
>> 
>> Nothing is switching to tty7 as I'm connected via UART so different
>> output.
>> Anyway weston starts properly on tty7 and is displayed correctly on 
>> the
>> display.
> 
> Well, Weston may start and be displayed, but are you sure the local
> console's current VT is VT7?

I can. If I connect a keyboard, Ctrl+Alt+F1 => Black screen, Ctrl+Alt+F7 
=> weston


>> > Do you mean that the device stops responding in the network when you
>> > say you can't open an ssh session? Like a kernel hang or panic?
>> No, ssh can connect (I get the content of /etc/issue.net) but after 
>> that
>> it hangs and will not ask for the password.
>> Or if I had an ssh connection already opend, and want to "ps aux" if
>> weston still running. I call "ps aux" and it will never show anything 
>> or
>> stop. It just hangs in there.
> 
> Huh. I wonder if Weston(-launch) is attempting to control the serial 
> tty
> somehow...
> 
> Does a simple 'echo foo' work instead of 'ps'?

further testing revealed, that if I'm fast enough ps aux will output 
stuff but stop at one point.

So I guess ps stops working, when "It" happens. Whatever "It" is.


>> > Are you unable to switch vts after exiting weston?
>> Ctrl+Alt+F1? Never tried, but I guess if I can, I would be able to
>> login, cause a login via UART (which is the same as locally) hangs 
>> too.
> 
> Well, would be nice to know if your serial tty is jammed or if it is
> actually the login procedure... sounds like the tty, though. But that
> doesn't explain ssh login getting stuck.
> 

How can I check if tty is jammed?


>> > weston-launch is the proper way, as a normal user. If you use
>> > weston-launch with --tty, I think you usually also want --user other
>> > than root. IIRC these two options usually go together.
>> 
>> I tried weston-launch without --tty too.
> 
> Unfortunately I don't have much experience in launching weston from a
> serial connection. I would recommend still trying to use weston-launch
> with both --tty and --user and using a normal user as the user, not
> root.
> 
> You may need to be root to run openvt and/or weston-launch. Please try
> also to make openvt switch (-s) to the new VT before it execs
> weston-launch.
> 
> You might also try weston-launch with --tty and --user but without
> openvt.

As --user is dedicated to root; weston-launch with --user and --tty 
starts but doesn't work either as
XGD_RUNTIME_DIR is then root's not that from the user.
-----
libwayland: unable to open lockfile /run/user/0/wayland-0.lock check 
permissions
-----

So currently I can run weston-launch only with openvt, with or without 
--tty and not with --user.


Any further ideas? ... As I run the app in kiosk mode and don't need to 
stop weston, it is just annoying, that I have to reboot when I sometimes 
need to restart weston.

Cheers,
Thilo