Crash with lilv 0.26.2

[dvzrv]

Describe the bug
Hi! 👋

I'm packaging this project for Arch Linux

After upgrading to lilv 0.26.2, muse crashes on start.
Related downstream bug report (also has a backtrace): https://gitlab.archlinux.org/archlinux/packaging/packages/muse/-/issues/2

To Reproduce
Steps to reproduce the behavior:

1. Install lilv 0.26.2 and muse 4.2.1
2. Start muse4 (e.g. in the terminal)
3. Crash during lv2 plugin loading

Expected behavior
Muse doesn't crash with lilv 0.26.2.

Screenshots
n/a

Desktop (please complete the following information):

• OS: Arch Linux
• Desktop n/a

Additional context

The backtrace suggests a crash due to lilv, but as other plugin hosts (e.g. ardour) work with lilv, I'm unsure what the underlying cause is.

[terminator356]

Ooh! Thanks for the report.
Thanks to the OP for the backtrace.
It seems to indicate the crash is in lilv or sord, not in muse.
All muse is doing is innocently calling lilv_plugin_get_uis(), with a valid handle. The rest is up to lilv.

I'm using 0.24.26.
Major upgrades including lilv-0.26.2 are available here.
Give me some time. (I need to upgrade anyway.)

Meanwhile however... From the looks of it, this might be a misbehaving LV2 plugin.
Or else a faulty lilv/sord.

The fact that one poster said he had to install a bunch of plugins to make the crash happen
is a bit of a red flag.

Not sure why the other DAWs don't crash. Are you sure the same plugins were used?
Possible explanation:
The other DAW's might use different methods.
For example they might ask only for specific plugin UIs, only when instantiating the plugin's UI.

Thanks.
Tim.

[terminator356]

Upgrade complete.
No crash here.

However, Arch Linux's lv2-plugins group contains many more LV2 plugins than here on openSusE Tumbleweed.

More evidence that it might be a misbehaving plugin.

If possible, if you could ask the OP the run MusE with the -D command line option.
This will print a bunch of debug information, including plugin loading progress,
which isn't shown in a backtrace.

Hopefully that should indicate the exact plugin where loading is failing.

Thanks.

[dvzrv]

I ran muse4 -D locally and the last thing I see is:

lilv_world_get_unique(): warning: Subject <http://aidadsp.cc/plugins/aidadsp-bundle/rt-neural-loader#DPF_UI> has multiple <http://lv2plug.in/ns/extensions/ui#binary> properties
[1]    1010343 segmentation fault (core dumped)  muse4 -D

[terminator356]

Hi thanks very much for the test.

The problem is definitely with the aidadsp plugin.
Your post shows it, and the OP's backtrace contains info that definitely matches aidadsp.
The backtrace shows the number of ports and so on, which indicates that it crashes when reading aidadsp:

#3  0x00007f5601b2d637 in MusECore::initLV2 () at /usr/src/debug/muse/muse-4.2.1/src/muse/lv2host.cpp:546
        info = @0x55bb4391a740: 
...
 _pluginFlags = 8, _portCount = 28, _inports = 1, _outports = 1, _controlInPorts = 21, _controlOutPorts = 3, _eventInPorts = 1, _eventOutPorts = 1, _freewheelPortIdx = 0, _latencyPortIdx = 0, _enableOrBypassPortIdx = 17,
...

Can you please try to fully instantiate aidadsp, with UI, in other DAWs like Ardour or QTractor?
Theoretically aidadsp should not even show up in those DAWs, or crash them as well.

I downloaded the ready-to-use aidadsp and it worked fine here. I did not build it from source.

This suggests that the Arch build of aidadsp has something wrong.

Thanks.
Tim.

[Dunravin]

Hello, I was also experiencing the same.

lilv_world_get_unique(): warning: Subject <http://aidadsp.cc/plugins/aidadsp-bundle/rt-neural-loader#DPF_UI> has multiple <http://lv2plug.in/ns/extensions/ui#binary> properties
[1]    1010343 segmentation fault (core dumped)  muse4 -D

I tried removing all the aida-x packages which did advance the start up but only to hang on other plugins and finish with the seg fault.

I checked in /var/cache/pacman/pkg/ and found I had lilv-0.24 in there so I downgraded to that.

running muse4 then failed with a cannot lock memory:: Cannot allocate memory error.

After setting

/etc/systemd/system.conf  
/etc/systemd/user.conf
DefaultLimitMEMLOCK=128M

and a relog I managed to get Muse to start.

I put back all the aida-x packages and muse is still loading successfully.

looking very much like there's something up with Arch's lilv-0.26 and I see there's an open bug report for this issue.

[dvzrv]

@terminator356 I see no issue in e.g. ardour (which also uses lilv) for the plugin and am able to load it.

Maybe @drobilla has an idea?

[drobilla]

Probably this lv2/lilv@d3d8a43

If so, because the UI description has multiple distinct binaries (which won't work, but shouldn't crash with that fix)

[terminator356]

Thanks, and hi Dave!
Does this mean these plugins won't be able to open a UI at all, because there are multiple binaries?
If not, then it seems the real cause of these warnings has not been addressed.
Maybe a problem with how the plugins were built for Arch?
As noted, my downloaded ready-to-run aida plugin did not show me that warning and did not crash.

[dvzrv]

Probably this lv2/lilv@d3d8a43

@drobilla excellent, that was it! I'll patch the package with this commit 👌

[drobilla]

@terminator356 A plugin that does describe multiple binaries won't work (lilv has no way of knowing which to load), but in this case the issue was multiple installed copies of the same plugin, which is a lilv bug (and a sloppy system, but it should work anyway). It's purely a data thing, so how the plugins are built shouldn't matter.

The UI should work again with lv2/lilv@8d9687d