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

[Derek Foreman]

On 19/03/15 09:58 AM, Thilo Cestonaro wrote:
> 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" :(

ulimit -c unlimited
before you launch anything, and the segfaulting app should leave a core
file behind...

but I think what you really want to do is attach gdb to the running
weston process (gdp -p <pid>), not start weston-launch under gdb...

Very surprised to see weston-launch receiving SIGSEGV.  Even so, it's
probably easier to attach gdb to weston-launch after starting it than to
go through all the trouble to use gdbsever.  :)

Probably a silly suggestion, but can you try
weston-launch -- --use-pixman
and see if you get the same problem on exit?

If you're connecting over serial, I'm guessing you're not on typical
desktop hardware, so a potentially funny GL stack may be in the picture.

> 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) ?

If the script is just weston-launch, how did you hook up gdbserver?

> 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
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