VST3PluginTestHost crashes when closing 2 or more instances of GUI of same plugin in particular order

Developer VST 3 SDK
1

Environment:
OS: Windows 10 Home, 64bit, version 1903, build 18362.592
Host: VST3PluginTestHost Standalone - Version 2.8.0 Build 224

Steps to reproduce:

  1. Open VST3PluginTestHost then load 2 Note Expression Synth With UI.
  2. Delete Note Expression Synth With UI (1).
  3. Delete Note Expression Synth With UI (2).
  4. Quit VST3PluginTestHost. Crash occurs at this step.

These steps are only for 2 instances case, but crash also occurs when the GUIs are 3 or more.

I observed that after step 2, pressing e button on VST Rack to close remaining GUI doesn’t work. And pressing e again open another instance of GUI.

Link below is a video to demonstrate crash.
https://drive.google.com/file/d/1tvum-lVeda5D0Z9T_QwWGDF4fOUjzAX3/view?usp=sharing

Crash also happened with:

  • AGain VST 3
  • VST3 Host Checker

Plugins are built from latest clone of vst3sdk GitHub Repository (vstsdk3614_03_12_2019_build_24).

Relevant part of VST3PluginTestHost.LOG:

===================================================================
VST3PluginTestHost.exe 2.8.0 Build 224 - 27.1.2020 11:35
-------------------------------------------------------------------
Timestamp is 5da9ce93 (Fri Oct 18 23:39:15 2019)
C:\Program Files\Steinberg\VST3PluginTestHost\VST3PluginTestHost.exe
-------------------------------------------------------------------
Exception code: C0000005 ACCESS_VIOLATION
Fault address:  404A580A 01:004A480A C:\Program Files\Steinberg\VST3PluginTestHost\VST3PluginTestHost.exeBytes at CS:EIP:
ff 50 60 48 8b 83 88 00 00 00 48 83 78 30 00 74
38 48 8b 03 48 8b cb ff 90 d8 02 00 00 48 85 c0


===================================================================
VST3PluginTestHost.exe 2.8.0 Build 224 - 27.1.2020 11:36
-------------------------------------------------------------------
Timestamp is 5da9ce93 (Fri Oct 18 23:39:15 2019)
C:\Program Files\Steinberg\VST3PluginTestHost\VST3PluginTestHost.exe
-------------------------------------------------------------------
Exception code: C0000005 ACCESS_VIOLATION
Fault address:  677A93D0 5DA9CE93:5DA9CE93 C:\Program Files\Steinberg\VST3PluginTestHost\VST3PluginTestHost.exe
2

Thanks for the report we will check this…

3

i could reproduce it, and fix it… will be part of the next SDK update.
Thanks for reporting

4

Thanks for the fix. I’ll wait for next release.