LB process sticking around with high CPU

HenryLoenwind · October 31, 2021, 6:17pm

I just quit my 2 LB instances because the computer got quite sluggish so I wanted to reboot it (it’s just a mini-PC after all). However, before I could hit the reboot button, I noticed the CPU load still being at 100% and investigated:

Is there anything I can do to help in debugging this “process stays after closing the program” issue?

LightBurn · October 31, 2021, 6:20pm

Do this, and email or post the stack trace from the hung application’s main thread:

HenryLoenwind · October 31, 2021, 6:37pm

Darn, I did not expect such a quick response or I would have waited with cleaning up.

I’ll keep an eye open for this issue. I think this may happen regularly, I’ve been rebooting every couple of days. Didn’t think much of it, the hardware in those 100€ PCs is laughable weak… (On the other hand…how do they make a working PC that cheap? )

HenryLoenwind · November 4, 2021, 6:42pm

ntoskrnl.exe!KeSynchronizeExecution+0x5b66
ntoskrnl.exe!KeWaitForSingleObject+0x1460
ntoskrnl.exe!KeWaitForSingleObject+0x98f
ntoskrnl.exe!KeWaitForSingleObject+0x233
ntoskrnl.exe!ExWaitForRundownProtectionRelease+0x7dd
ntoskrnl.exe!KeWaitForSingleObject+0x3a29
ntoskrnl.exe!KiCheckForKernelApcDelivery+0x2b
ntoskrnl.exe!ExReleaseResourceAndLeaveCriticalRegion+0xc2
win32kbase.sys+0x9159f
win32kfull.sys!NtUserMsgWaitForMultipleObjectsEx+0x519
0x0000000000000000
win32u.dll!NtUserMsgWaitForMultipleObjectsEx+0x14
USER32.dll!MsgWaitForMultipleObjectsEx+0x9e
Qt5Core.dll!QEventDispatcherWin32::processEvents+0x394
qwindows.dll!qt_plugin_query_metadata+0x1dc9
LightBurn.exe+0x305402
LightBurn.exe+0xde774
LightBurn.exe+0x3f3d24
Qt5Core.dll!QMetaObject::activate+0x641
Qt5Widgets.dll!QAction::activate+0x10e
Qt5Widgets.dll!QAbstractButton::click+0x143
Qt5Widgets.dll!QAbstractButton::mouseReleaseEvent+0x8c
Qt5Widgets.dll!QToolButton::mouseReleaseEvent+0xf
Qt5Widgets.dll!QWidget::event+0xdc
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x7f3
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Widgets.dll!QApplicationPrivate::sendMouseEvent+0x3f3
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0x2ab5
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0xb45
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x1a97
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Gui.dll!QGuiApplicationPrivate::processMouseEvent+0x8c1
Qt5Gui.dll!QWindowSystemInterface::sendWindowSystemEvents+0x92
Qt5Core.dll!QEventDispatcherWin32::processEvents+0xde6
USER32.dll!CallWindowProcW+0x3f8
USER32.dll!DispatchMessageW+0x259
Qt5Core.dll!QEventDispatcherWin32::processEvents+0x5b0
qwindows.dll!qt_plugin_query_metadata+0x1dc9
Qt5Core.dll!QEventLoop::exec+0x1cb
Qt5Core.dll!QCoreApplication::exec+0x141
LightBurn.exe+0xb09e
LightBurn.exe+0xb139
LightBurn.exe!FT_WriteEE+0x2bae94
LightBurn.exe!FT_WriteEE+0x2b9f5b
KERNEL32.DLL!BaseThreadInitThunk+0x14
ntdll.dll!RtlUserThreadStart+0x21

Guess this one is the main thread? At least it has the entry in the exe and runs the event loop.

This is the thread list:

And this is the second instance that’s also hanging:

ntoskrnl.exe!KeSynchronizeExecution+0x5b66
ntoskrnl.exe!KeWaitForSingleObject+0x1460
ntoskrnl.exe!KeWaitForSingleObject+0x98f
ntoskrnl.exe!KeWaitForSingleObject+0x233
ntoskrnl.exe!ExWaitForRundownProtectionRelease+0x7dd
ntoskrnl.exe!KeWaitForSingleObject+0x3a29
ntoskrnl.exe!KeSynchronizeExecution+0x3140
Qt5Core.dll!QCoreApplicationPrivate::sendPostedEvents+0x27a
qwindows.dll!qt_plugin_query_metadata+0x1def
Qt5Core.dll!QEventDispatcherWin32::processEvents+0x682
qwindows.dll!qt_plugin_query_metadata+0x1dc9
LightBurn.exe+0x305402
LightBurn.exe+0x3066cd
LightBurn.exe+0xdfb5d
LightBurn.exe+0xf578b
LightBurn.exe+0x3f3d24
Qt5Core.dll!QMetaObject::activate+0x641
Qt5Widgets.dll!QAbstractButton::clicked+0xa7
Qt5Widgets.dll!QAbstractButton::click+0x199
Qt5Widgets.dll!QAbstractButton::mouseReleaseEvent+0x8c
Qt5Widgets.dll!QWidget::event+0xdc
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x7f3
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Widgets.dll!QApplicationPrivate::sendMouseEvent+0x3f3
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0x2ab5
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0xb45
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x1a97
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Gui.dll!QGuiApplicationPrivate::processMouseEvent+0x8c1
Qt5Gui.dll!QWindowSystemInterface::sendWindowSystemEvents+0x92
Qt5Core.dll!QEventDispatcherWin32::processEvents+0xde6
USER32.dll!CallWindowProcW+0x3f8
USER32.dll!DispatchMessageW+0x259
Qt5Core.dll!QEventDispatcherWin32::processEvents+0x5b0
qwindows.dll!qt_plugin_query_metadata+0x1dc9
LightBurn.exe+0x305402
LightBurn.exe+0x3066cd
LightBurn.exe+0xdfb5d
LightBurn.exe+0xf578b
LightBurn.exe+0x3f3d24
Qt5Core.dll!QMetaObject::activate+0x641
Qt5Widgets.dll!QAbstractButton::clicked+0xa7
Qt5Widgets.dll!QAbstractButton::click+0x199
Qt5Widgets.dll!QAbstractButton::mouseReleaseEvent+0x8c
Qt5Widgets.dll!QWidget::event+0xdc
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x7f3
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Widgets.dll!QApplicationPrivate::sendMouseEvent+0x3f3
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0x2ab5
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0xb45
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x1a97
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Gui.dll!QGuiApplicationPrivate::processMouseEvent+0x8c1
Qt5Gui.dll!QWindowSystemInterface::sendWindowSystemEvents+0x92
Qt5Core.dll!QEventDispatcherWin32::processEvents+0xde6
USER32.dll!CallWindowProcW+0x3f8
USER32.dll!DispatchMessageW+0x259
Qt5Core.dll!QEventDispatcherWin32::processEvents+0x5b0
qwindows.dll!qt_plugin_query_metadata+0x1dc9
LightBurn.exe+0x305402
LightBurn.exe+0x3066cd
LightBurn.exe+0xdfb5d
LightBurn.exe+0xf578b
LightBurn.exe+0x3f3d24
Qt5Core.dll!QMetaObject::activate+0x641
Qt5Widgets.dll!QAbstractButton::clicked+0xa7
Qt5Widgets.dll!QAbstractButton::click+0x199
Qt5Widgets.dll!QAbstractButton::mouseReleaseEvent+0x8c
Qt5Widgets.dll!QWidget::event+0xdc
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x7f3
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Widgets.dll!QApplicationPrivate::sendMouseEvent+0x3f3
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0x2ab5
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0xb45
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x1a97
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Gui.dll!QGuiApplicationPrivate::processMouseEvent+0x8c1
Qt5Gui.dll!QWindowSystemInterface::sendWindowSystemEvents+0x92
Qt5Core.dll!QEventDispatcherWin32::processEvents+0xde6
USER32.dll!CallWindowProcW+0x3f8
USER32.dll!DispatchMessageW+0x259
Qt5Core.dll!QEventDispatcherWin32::processEvents+0x5b0
qwindows.dll!qt_plugin_query_metadata+0x1dc9
LightBurn.exe+0x305402
LightBurn.exe+0x3066cd
LightBurn.exe+0xdfb5d
LightBurn.exe+0xf578b
LightBurn.exe+0x3f3d24
Qt5Core.dll!QMetaObject::activate+0x641
Qt5Widgets.dll!QAbstractButton::clicked+0xa7
Qt5Widgets.dll!QAbstractButton::click+0x199
Qt5Widgets.dll!QAbstractButton::mouseReleaseEvent+0x8c
Qt5Widgets.dll!QWidget::event+0xdc
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x7f3
Qt5Core.dll!QCoreApplication::notifyInternal2+0xb9
Qt5Widgets.dll!QApplicationPrivate::sendMouseEvent+0x3f3
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0x2ab5
Qt5Widgets.dll!QSizePolicy::QSizePolicy+0xb45
Qt5Widgets.dll!QApplicationPrivate::notify_helper+0x140
Qt5Widgets.dll!QApplication::notify+0x1a97

This thread also uses significant CPU time:

ntoskrnl.exe!KeSynchronizeExecution+0x5b66
ntoskrnl.exe!KeWaitForSingleObject+0x1460
ntoskrnl.exe!KeWaitForSingleObject+0x98f
ntoskrnl.exe!KeWaitForSingleObject+0x233
ntoskrnl.exe!ExWaitForRundownProtectionRelease+0x7dd
ntoskrnl.exe!KeWaitForSingleObject+0x3a29
ntoskrnl.exe!KeSynchronizeExecution+0x3140
quartz.dll!AMGetErrorTextW+0x417b0
quartz.dll!AMGetErrorTextW+0x4208d
quartz.dll!AMGetErrorTextW+0x42837
quartz.dll!AMGetErrorTextW+0x3feee
quartz.dll!AMGetErrorTextW+0x3ddbe
quartz.dll!AMGetErrorTextW+0x3cfe5
quartz.dll!AMGetErrorTextW+0xfc031
quartz.dll!AMGetErrorTextW+0xfbac9
quartz.dll!AMGetErrorTextW+0x53b2
qcap.dll!DllCanUnloadNow+0x23e29
qcap.dll!DllCanUnloadNow+0x23cac
KERNEL32.DLL!BaseThreadInitThunk+0x14
ntdll.dll!RtlUserThreadStart+0x21

I’ll leave them running for now, so in the next couple of hours I can pull other diagnostics. (I’m frustrated that my laser went from “perfect cuts” to “halfway through is fine with you, ain’t it?” and I just can’t find the reason. Need. To. Do. Something. Completely. Different.)

LightBurn · November 8, 2021, 7:57pm

Unfortunately I don’t see anything in there that I recognize. It looks like it might be hanging while waiting for a system resource of some kind, but I can’t think of anything in LightBurn itself that would do that.

LightBurn · November 8, 2021, 8:03pm

One thing to try:

Open a Windows file explorer
Browse to C:\Program Files\LightBurn
Find the file ‘LBFileDialog.exe’
Rename it to something (just add .bak to the name, for example)

Re-run and see if you get the issue any more. We’ve had a small number of users (3 maybe?) report an issue with this, and I haven’t figured out why. The LBFileDialog program just shows the file open / save / import window, and passes information back to LightBurn. If it can’t be found, the software falls back to using the internal one instead of the launchable version.

HenryLoenwind · November 16, 2021, 5:33pm

Ok, I’ve renamed the LBFileDialog and will watch it closely.

One effect I already noticed: When I “Run GCode” the laser starts a fraction of a second after I confirm the File Open dialog now. This took 5-15 seconds before and from time to time it wouldn’t do anything. Hard to say if there’s a speed difference when opening lbrn2 files, there’s actual processing involved that needs CPU cycles.

system · December 16, 2021, 5:33pm

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