Crash of Carla when saving a patch in Zebra2 v7420

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AlbertoZ
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Joined: Thu Nov 23, 2017 10:08 am

Crash of Carla when saving a patch in Zebra2 v7420

Postby AlbertoZ » Sat Jun 09, 2018 8:59 pm

Hello FalkTx,

I was trying the latest build of u-he Zebra v2.8 in Carla.
https://www.reddit.com/r/UheOnLinux/comments/8n6mrk/diva_repro1_satin_and_zebra2_rev7420/
It seems to run very smooth, until I try to save a patch ==> Carla crashes.
This also happens in Ardour. It doesn't, instead, in Bitwig & Renoise.
Then I ran carla --gdb, load the Zerba VST and save the patch and this is what I got:

    alberto@XPS-8300 ~/Scrivania/Zebra2-7420 $ carla --gdb
    GNU gdb (Ubuntu 7.11.1-0ubuntu1~16.5) 7.11.1
    Copyright (C) 2016 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law. Type "show copying"
    and "show warranty" for details.
    This GDB was configured as "x86_64-linux-gnu".
    Type "show configuration" for configuration details.
    For bug reporting instructions, please see:
    <http://www.gnu.org/software/gdb/bugs/>.
    Find the GDB manual and other documentation resources online at:
    <http://www.gnu.org/software/gdb/documentation/>.
    For help, type "help".
    Type "apropos word" to search for commands related to "word"...
    Reading symbols from /usr/bin/python3...(no debugging symbols found)...done.
    (gdb) run
    Starting program: /usr/bin/python3 /usr/share/carla/carla --with-appname=/usr/bin/carla --with-libprefix=/usr --gdb
    [Thread debugging using libthread_db enabled]
    Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
    LRDF Support not available (LADSPA-RDF will be disabled)
    [New Thread 0x7fffe7684700 (LWP 6511)]
    Carla 1.9.8 (2.0-beta6) started, status:
    Python version: 3.5.2
    Qt version: 5.5.1
    PyQt version: 5.5.1
    Binary dir: /usr/lib/carla
    Resources dir: /usr/share/carla/resources
    [New Thread 0x7fffdcb4b700 (LWP 6512)]
    [New Thread 0x7fffd23a9700 (LWP 6513)]
    [New Thread 0x7fffd1970700 (LWP 6514)]
    [New Thread 0x7fffd116f700 (LWP 6515)]
    [New Thread 0x7fffd096e700 (LWP 6516)]
    libjack.so.0 loaded sucessfully!
    [New Thread 0x7fffdc0bb700 (LWP 6517)] <== Load of Zebra2 starts here
    [New Thread 0x7fffd016d700 (LWP 6518)]
    [New Thread 0x7fffcbda9700 (LWP 6519)]
    [New Thread 0x7fffcb5a8700 (LWP 6520)]
    [New Thread 0x7fffcb527700 (LWP 6521)]
    [New Thread 0x7fffcad26700 (LWP 6522)]
    [New Thread 0x7fffc93bd700 (LWP 6523)]
    [New Thread 0x7fffc8bbc700 (LWP 6524)]
    [New Thread 0x7fffc8b3b700 (LWP 6525)]
    [New Thread 0x7fffc89d9700 (LWP 6526)]
    [New Thread 0x7fffb99a0700 (LWP 6527)]
    [Thread 0x7fffb99a0700 (LWP 6527) exited]
    [New Thread 0x7fffb99a0700 (LWP 6528)]
    [Thread 0x7fffb99a0700 (LWP 6528) exited]

    Thread 1 "carla" received signal SIGSEGV, Segmentation fault.
    0x00007fffc98622aa in ?? () from /home/alberto/.u-he/Zebra2/Zebra2.64.so
    (gdb)

I know that this is not very informative. Any suggestions of what to look after?
I'm on Linux Mint 18.3.
Carla version is:

    carla --version
    LRDF Support not available (LADSPA-RDF will be disabled)
    Using Carla version 1.9.8 (2.0-beta6)
    Python version: 3.5.2
    Qt version: 5.5.1
    PyQt version: 5.5.1
    Binary dir: /usr/lib/carla
    Resources dir: /usr/share/carla/resources


Thanks in advance,

Alberto
Last edited by AlbertoZ on Sun Jun 10, 2018 11:40 am, edited 1 time in total.

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falkTX
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Joined: Sat Jan 09, 2010 3:04 pm

Re: Crash of Carla when saving a patch in Zebra2 v4720

Postby falkTX » Sun Jun 10, 2018 7:20 am

The u-he plugins are known to be crashy on opensource hosts.
They seem to expose some library symbols that conflict with general system shared libraries (glib?).
As the plugins are not opensource, we cannot really try different build methods and flags or even figure out what they are doing :(

That said, I added an option in Carla some time ago to specifically help with u-he plugins.
Enable experimental settings, then on the experimental section enable "global namespace".
this fixes some issues with u-he stuff, but then breaks other things - specially plugins that use same libraries that carla already does, like calf-fluidsynth and zynaddsubfx.

In case you already have that option enabled, then I am afraid there is not much I can do at all here.

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AlbertoZ
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Posts: 25
Joined: Thu Nov 23, 2017 10:08 am

Re: Crash of Carla when saving a patch in Zebra2 v7420

Postby AlbertoZ » Sun Jun 10, 2018 11:34 am

Thanks for the quick answer Felipe.
I do confirm that the "load Carla backend in the global namespace" is flagged.
I'll report this issue to abique.

Thanks again,

Alberto


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