Carla segfault with internal zynaddsubfx plugin - UI issue ?

[distrozapper]

Carla git commit 06753fc segfaults on following these steps:

1. open Carla (debug build)
2. add native zynaddsubfx plugin
3. open zyn's GUI via Carla button
4. change zyn's part number e.g from 1 to 2
5. close zyn's GUI via Carla button
6. open zyn's GUI again via Carla button --> Carla segfaults
   Packaged Carla version 1:0.5.0+git20130319-0~precise2 shows a crash/disappears from screen on step 6.
   Environment:
   kernel 3.2.0-38-lowlatency http://gareus.org/oss/lv2/b_synth is not listed in carla #40-Ubuntu SMP PREEMPT x86_64, linux mint 13 "maya" cinnamon on Intel Core I7 1.73GHz, upgraded by kxstudio-repos
   gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
   System patch level: dist-upgraded We 20 March 2013 06:15 CET,
   Carla setup:
   Main/Misc: Disable processing checks while scanning: DISABLED
   GUI refresh interval: 60ms
   Engine: Core: JACK/Single Client/800
   GUIs: OSC timeout 6000ms
   Advanced: All three options DISABLED

Backtrace:
CarlaEngine::getPlugin(0) [count:1]
CarlaEngine::osc_send_control_set_parameter_value(0, PARAMETER_ACTIVE, 1)
carla_show_gui(0, true)
CarlaEngine::getPlugin(0) [count:1]
Theme set to Cairo
Theme set to Cairo
carla_show_gui(0, false)
CarlaEngine::getPlugin(0) [count:1]
carla_show_gui(0, true)
CarlaEngine::getPlugin(0) [count:1]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7fffcc9f3700 (LWP 5035)]
0x00007ffff671959c in free () from /lib/x86_64-linux-gnu/libc.so.6
(gdb) bt
#0 0x00007ffff671959c in free () from /lib/x86_64-linux-gnu/libc.so.6
#1 0x00007fffde8298f5 in Fl_Group::init_sizes() ()

from /usr/lib/x86_64-linux-gnu/libntk.so.1
#2 0x00007fffde82986d in Fl_Group::Fl_Group(int, int, int, int, char const*) ()

from /usr/lib/x86_64-linux-gnu/libntk.so.1
#3 0x00007fffde866c9d in Fl_Window::Fl_Window(int, int, int, int, char const*) ()

from /usr/lib/x86_64-linux-gnu/libntk.so.1
#4 0x00007fffe150e058 in NioUI::NioUI (this=0x7fffc8e34900)

at zynaddsubfx/UI/NioUI.cpp:17

#5 0x00007fffe15583bd in MasterUI::MasterUI (this=0x7fffc8e345a0, master_=0x3f4c900,

exitprogram_=0x3f4c8d8) at zynaddsubfx/UI/MasterUI.cpp:2360

#6 0x00007fffe14a2fee in ZynAddSubFxPlugin::ZynThread::run (this=0x3f4c868)

at zynaddsubfx.cpp:434

#7 0x00007fffe1443db9 in CarlaThread::handleRoutine (this=0x3f4c868)

at ../../utils/CarlaThread.hpp:229

#8 0x00007fffe1443ddb in CarlaThread::_pthreadRoutine (this=0x3f4c868)

at ../../utils/CarlaThread.hpp:246

#9 0x00007ffff7bc4e9a in start_thread () from /lib/x86_64-linux-gnu/libpthread.so.0
#10 0x00007ffff6789cbd in clone () from /lib/x86_64-linux-gnu/libc.so.6
#11 0x0000000000000000 in ?? ()

(gdb)

FalkTX: I hope this helps. Feel free to ask for more info if you see me on #kxstudio.

[distrozapper]

I have found a way to delay the segfault by adding some action between steps 4 and 5:

4a) Click on the "EffType" dropdown menu, leaving "No Effect" (default), or open/close zyn's own keyboard.

Excecuting steps 5 and 6 does not lead to a segfault then. However zyn's part number has been reset to 1 (is this intended behaviour?
Changing the part number without any further action triggers a segfault on close/open GUI immediately.
Maybe this helps catching the issue.

[fundamental]

Commit d6825d8 seems to fix the issue on my system, but I do get the feeling that this may be covering up some weirdness in another portion of the code

[falkTX]

Thanks for the report.
ZynAddSubFX code is not exactly clean, so I'm pretty sure some other bug might come up later.
If you catch one, let me know.