[LMMS-devel] VST on amd64: sloppy libxcb locking assertion failure

[Thomas K. <gi...@so...>]

Hi there,

there (still) is a bug in LMMS which affects VSTs on
x86_64 plattform when LIBXCB_ALLOW_SLOPPY_LOCK is unset.

Some Gentoo users have reported there is no such issue on x86.

This affects both, 0.4.x versions and current trunk (IIRC it was
working for me in trunk around when 0.4.2 came out)

Whenever a VST GUI is loaded, LMMS crashes with:

-----------------------------
RemotePlugin::DebugMessage: creating editor
RemotePlugin::DebugMessage: creating GUI thread
RemotePlugin::DebugMessage: editor successfully created
Locking assertion failure.  Backtrace:
#0 /usr/lib/libxcb-xlib.so.0 [0x7fbb14f4797c]
#1 /usr/lib/libxcb-xlib.so.0(xcb_xlib_lock+0x17) [0x7fbb14f47ad7]
#2 /usr/lib/libX11.so.6 [0x7fbb16433590]
#3 /usr/lib/libX11.so.6(XGetWindowProperty+0x42) [0x7fbb16411962]
#4 /usr/lib/qt4/libQtGui.so.4 [0x7fbb1a9ffbfc]
#5 /usr/lib/libX11.so.6(XCheckIfEvent+0x79) [0x7fbb16406499]
#6 /usr/lib/qt4/libQtGui.so.4(_ZN18QX11EmbedContainer11embedClientEm+0x224)
[0x7fbb1aa001e4]
#7 /usr/lib64/lmms/libvstbase.so(_ZN9vstPlugin10showEditorEP7QWidget+0xeb)
[0x7fbb0bf0cd1b]
#8 /usr/lib64/lmms/libvestige.so(_ZN17vestigeInstrument8loadFileERK7QString+0x2ba)
[0x7fbaf685933a]
#9 /usr/lib64/lmms/libvestige.so(_ZN21vestigeInstrumentView10openPluginEv+0x5af)
[0x7fbaf68586bf]
#10 /usr/lib64/lmms/libvestige.so(_ZN21vestigeInstrumentView11qt_metacallEN11QMetaObject4CallEiPPv+0x4d)
[0x7fbaf685889d]
#11 /usr/lib/qt4/libQtCore.so.4(_ZN11QMetaObject8activateEP7QObjectiiPPv+0x275)
[0x7fbb1a2f45c5]
#12 /usr/lib/qt4/libQtGui.so.4(_ZN15QAbstractButton7clickedEb+0x37)
[0x7fbb1af2bd97] #13
lmms(_ZN12pixmapButton17mouseReleaseEventEP11QMouseEvent+0x9)
[0x545349]
#14 /usr/lib/qt4/libQtGui.so.4(_ZN7QWidget5eventEP6QEvent+0x7a0)
[0x7fbb1a9ce4f0]
#15 /usr/lib/qt4/libQtGui.so.4(_ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent+0xbd)
[0x7fbb1a98158d]
#16 /usr/lib/qt4/libQtGui.so.4(_ZN12QApplication6notifyEP7QObjectP6QEvent+0x7f3)
[0x7fbb1a9895c3]
#17 /usr/lib/qt4/libQtCore.so.4(_ZN16QCoreApplication14notifyInternalEP7QObjectP6QEvent+0x83)
[0x7fbb1a2e2433]
#18 /usr/lib/qt4/libQtGui.so.4(_ZN19QApplicationPrivate14sendMouseEventEP7QWidgetP11QMouseEventS1_S1_PS1_R8QPointerIS0_E+0x108)
[0x7fbb1a98aa98] #19 /usr/lib/qt4/libQtGui.so.4 [0x7fbb1a9e39fc] lmms:
xcb_xlib.c:73: xcb_xlib_lock: Zusicherung »!c->xlib.lock« nicht erfüllt.
-----------------------------------


This should be fixable quite easily though.

Cheers,
Thomas