hang-up on 1.2.0.3

[dfelippa]

Since I upgraded to version 2.0.3 uvnc tends to hang indefenitely when I copy (ctrl+c) anything on the remote machine clipboard.
It only works again if the service is restarted on the remote machine.

We're using win 7 64 on the client side and win 7 32 or 64 on the server side (controlled side)

Could you please double check for some error?
I wonder why other people are not finding this bug. We tested on many different machines and it hangs very often.

Thank you
Dennis

[Rudi De Vos]

what dat type do you pass ?
txt,rtf,bitmaps,html
Or it happen with all data types.

I gonna try to repeat it, but it is possible that it only manifest himself on systems with another clipboard
application active. I most cases, errors like this are not general... Is there some specific software running
that could be manipulating the clipboard ?

since upgrade... what was the previous verion ?
And you can confirm that with the old version you didn't had any issue's with the clipboard !
Our revision sytem allow to do some file differences to see what changed around the clipboard model.

[Rudi De Vos]

We can not repeat it
server : win7 x64
tested with viewer 1203 1906
copy txt, images html
tried with and without system hook

More info needed

[Heinzi]

I can reproduce the issue. 1.2.0.1 works fine, 1.2.0.3 hangs.

Here's how I did it:

1. Start VNC Server 1.2.0.3.
2. Connect with VNC Viewer 1.0.8.2. Do the following inside the VNC session:
3. Start Internter Explorer.
4. Navigate to www.uvnc.com
5. Select the first few words of text with the mouse ("Ultra VNC is a powerful").
6. Hit Ctrl-C

Expected result: The remote session continues.
Actual result: The remote session freezes.

When doing the exact same steps with VNC Server 1.2.0.1, everything works fine. Tested with Windows 7 (Server) and Windows 8.1 (Viewer).

Hope that helps, best regards
Heinzi

[dfelippa]

It's incredible that you can't reproduce it. Must be something related to the locale since I tested in so many different machines and most of them hang. We are in Brazil and use either American or Brazilian ABNT keyboard

More information:
1) We use 1.2.0.3 on both sides (viewer and server)
2) It hangs immediately after pressing ctrl+c. The viewer won't refresh and won't accept any command.
2.1) If I open another viewer it will lock in a state like "negotiating protocol" and never really connects
2.2) Only after restarting the service I can connect again
3) Disabling clipbard transfer does not help
4) Previously we used versio 1.96, but I don't think it makes a difference since I tested it on clean machines as well.
5) There is no other clipboard application

[Rudi De Vos]

Can you also confirm that 1.2.0.1 worked

This would make it a lot simpler as code changes between 1.2.0.1 and 1.2.0.3 are minimal.


It could be a local or some timings...
The problem is that vnc run multiple threads , some code parts happen simultaneous but final need to work together.

[Heinzi]

I'll add some information in the hope that it's helpful:

* I don't think it's related to regional settings. I switched both viewer and server from de-AT to en-US and the problem still occurs.

* After the hang-up (hang-up #1, after Ctrl-C), remote mouse movements are still transmitted to the server (although the viewer does not show changes anymore). After closing the viewer, no reconnections are possible (as explained by dfelippa), but the server systray icon is still responsive.

* In this state, when you try to stop the server by choosing "Close VNC Connections", the server hangs completely (hang-up #2) and needs to be shut down using task manager. I managed to download the VNC server source and run it in Visual Studio, and this is where the thread hangs after hang-up #2:

Code: Select all

 	ntdll.dll!_ZwWaitForSingleObject@12()  + 0xc bytes	
 	ntdll.dll!RtlpWaitOnCriticalSection()  + 0xcf bytes	
 	ntdll.dll!RtlpEnterCriticalSectionContended()  + 0xac bytes	
 	ntdll.dll!_RtlEnterCriticalSection@4()  - 0x20cc3 bytes	
>	winvnc.exe!omni_mutex::lock()  Line 217 + 0x2f bytes	C++
 	winvnc.exe!omni_mutex_lock::omni_mutex_lock(omni_mutex & m={...}, int i=21)  Line 266	C++
 	winvnc.exe!vncServer::KillAuthClients()  Line 830 + 0x11 bytes	C++
 	winvnc.exe!vncMenu::WndProc(HWND__ * hwnd=0x01211a04, unsigned int iMsg=273, unsigned int wParam=40002, long lParam=0)  Line 1152 + 0x13 bytes	C++
 	user32.dll!__InternalCallWinProc@20()  + 0x23 bytes	
 	user32.dll!UserCallWinProcCheckWow()  + 0x1a6 bytes	
 	user32.dll!DispatchMessageWorker()  + 0x200 bytes	
 	user32.dll!_DispatchMessageA@4()  + 0x10 bytes	
 	winvnc.exe!imp_desktop_thread(void * lpParam=0x0018e618)  Line 971 + 0xf bytes	C++
 	kernel32.dll!@BaseThreadInitThunk@12()  + 0xe bytes	
 	ntdll.dll!__RtlUserThreadStart()  + 0x24 bytes	
 	ntdll.dll!__RtlUserThreadStart@8()  + 0x1b bytes	

I tried to break execution after hang-up #1, but I noticed nothing extraordinary. The threads seem to be waiting in some kind of message loop:

Code: Select all

imp_desktop_thread: while (GetMessage(&msg,0,0,0) != 0)
Main Thread: WaitForSingleObject( threadHandle, INFINITE );

I'm not a C++ developer, but if there's any more debug information I can provide to help, please say so.

[Prisma]

We've got the same problem since 1.2.0.3. For security reasons we changed the rollout from 1.2.0.1 to 1.2.0.3.... ARG!

The freeze occurs while doing ctrl+C/ctrl+V with simple marked text. Horrible, standard support scenario. 500 customers affected. Need a urgent fix.

[dfelippa]

I tested with 1.2.01 here is the result:

client 2.03 server 2.03 -> hangs
client 2.01 server 2.03 -> hangs

client 2.01 server 2.01 -> ok
client 2.03 server 2.01 -> ok

Also sometimes - in the cases when it hangs - copying from the notepad will not hang, but, for an instance, selecting page contents displayed on internet explorer and copying it always hangs.

[Rudi De Vos]

I was able to repeat it... when ctrl-c on a word doc.
It's not a crash, but a deadlock

[Rudi De Vos]

found
update 866 OK , 867 fail, only one line was changed... ( 2014-07-29 20:53:43 )

http://www.uvnc.eu/download/1203/winvnc_test.zip

Please test...

[Prisma]

cause we weren't able to repeat it locally, we just rolled it out. Things could only get better... I'll give you a feedback asap, but I think dfelippa is faster. He seems to have a test scenario.

[Prisma]

For testing we need also a win2000 version

[dfelippa]

This fixes them problem.

Thank you very much for your dedication and prompt solution to this issue.

Also, thank you for creating, maintaining and making uvnc available for us all.

One tip for those who want to try the test link in this post: first download some other file from downloads, then click on the test link, otherwise the test file will not download .

Best Regards,
Dennis

[dfelippa]

Just one more thing: could you please generate binaries for x86 and xp?
Thank you,
Dennis

[Rudi De Vos]

http://www.uvnc.eu/download/1203/winvnc_testw2k.zip

[Heinzi]

I can also confirm that this fixes the problem. Thanks for the great support and the fast fix (and for ultravnc in general, of course)!

Should we deploy the fixed 1.2.0.3 version or do you plan to release an official update (1.2.0.4?) in the near future?

Best regards
Heinzi

[Rudi De Vos]

To complex to keep the same number, it's already hard enough to backtrace problems

Update will be 1.2.0.4