Invalid access to memory

Hello,

I have found a reproducible crash-bug, which only occurs in a strange race condition but could (and did :P) still happen ;)

Reproduce it as follows:

Open a SSH (SFTP) connection to a server and open a file on that server with a extenal texteditor (in my case Sublime Text 3).

Open a connection to a server that is not responding or very slow, I did this via a wrongly configured protocol-url -> just click this link then: winscp-ftps://web78:notarealpassword@webspace34.do.de

Now, while it tries to connect to the server on the unused port 990, save your file in the texteditor.

A crash occurs. This happens in 5.6.2 beta and 5.6.3 nightly.

So long,
Tobias


Screenshot:
https://screenshot.tbspace.de/onjehtxgcfa.png

Log:
WinSCP 5.6.3 (nightly build 4810 - 2014-11-09)

Error message:
Invalid access to memory.

Stack trace:
[000280F4] TCustomScpExplorerForm::AddQueueItem
[007E28B2] std::basic_filebuf<wchar_t, std::char_traits<wchar_t> >::imbue
[007E491A] _ungetch
[007E1894] std::basic_filebuf<wchar_t, std::char_traits<wchar_t> >::uflow
[77E2B466] ntdll.dll
[77DE012E] ntdll.dll.KiUserExceptionDispatcher
[0007A7A5] TCopyParamRule::TCopyParamRule
[00078774] std::vector<TEditorManager::TFileData, std::allocator<TEditorManager::TFileData> >::_Insert_n
[00035681] TCustomScpExplorerForm::Idle
[00058377] TNonVisualDataModule::DoIdle
[00058334] TNonVisualDataModule::SetScpExplorer
[0035FC20] System::Classes::TObservers::AddObserver
[773662F7] USER32.dll
[77366D35] USER32.dll
[773677BF] USER32.dll
[77367885] USER32.dll.DispatchMes

[007E2F1D] __Atexit
[007E44F7] C3025_3
[0007A7C7] TCopyParamRule::operator ==
[00078774] std::vector<TEditorManager::TFileData, std::allocator<TEditorManager::TFileData> >::_Insert_n
[00035681] TCustomScpExplorerForm::Idle
[00058377] TNonVisualDataModule::DoIdle
[00058334] TNonVisualDataModule::SetScpExplorer
[0035FC20] System::Classes::TObservers::AddObserver
[773662F7] USER32.dll
[77366D35] USER32.dll
[773677BF] USER32.dll
[77367885] USER32.dll.DispatchMessageW

Duplicate post:
https://winscp.net/forum/viewtopic.php?t=14535

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.17

Error message:
Invalid access to memory.

Stack trace:
(0041AE7C) System::DynArraySetLength
(00F85D26) C5296_3
(00F87D8E) ____ExceptionHandler
(00F84B48) __ExceptionHandler
(00089BEF) ntdll.dll
(00070AB1) ntdll.dll.KiUserExceptionDispatcher
(0041AF9D) System::DynArraySetLength
(00008B77) TCustomScpExplorerForm::AddQueueItem
(000153E2) TCustomScpExplorerForm::ExecutedFileChanged
(00071809) TEditorManager::CheckFileChange
(0006F7F6) TEditorManager::Check
(00018C78) TCustomScpExplorerForm::Idle
(00049A87) TNonVisualDataModule::DoIdle
(00049A44) TNonVisualDataModule::SessionIdleTimerTimer
(003A4568) System::Classes::_18201
(0001D4F9) USER32.dll
(00027CA4) USER32.dll
(0002A5D3) USER32.dll
(00018517) USER32.dll
(0001805B) USER32.dll.DispatchMessageW

(00F86391) C5296_3
(00F8796B) _ReThrowException
(0007182B) TEditorManager::CheckFileChange
(0006F7F6) TEditorManager::Check
(00018C78) TCustomScpExplorerForm::Idle
(00049A87) TNonVisualDataModule::DoIdle
(00049A44) TNonVisualDataModule::SessionIdleTimerTimer
(003A4568) System::Classes::_18201
(0001D4F9) USER32.dll
(00027CA4) USER32.dll
(0002A5D3) USER32.dll
(00018517) USER32.dll
(0001805B) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.

<Try to describe precise steps that lead to the problem (where do you click, what keys do you press, what do you see, etc.)>
<If relevant, consider attaching a session log file or a screenshot)>

WinSCP 5.17.3

Error message:
Acceso a memoria no válido

Traza de la pila:
(0041B059) System::DynArraySetLength
(00F876DE) C5296_0
(00F89746) ____ExceptionHandler
(00F86500) __ExceptionHandler
(00087E3F) ntdll.dll
(000732C1) ntdll.dll.KiUserExceptionDispatcher
(0041B215) System::DynArraySetLength
(00008B92) TCustomScpExplorerForm::AddQueueItem
(000153E2) TCustomScpExplorerForm::ExecutedFileChanged
(000719B5) TEditorManager::CheckFileChange
(0006F9A2) TEditorManager::Check
(00018C78) TCustomScpExplorerForm::Idle
(00049A6F) TNonVisualDataModule::DoIdle
(00049A2C) TNonVisualDataModule::SessionIdleTimerTimer
(003A47E0) System::Classes::_18201
(00043449) USER32.dll
(00023F87) USER32.dll
(000230D9) USER32.dll
(00022EBB) USER32.dll.DispatchMessageW

(00F87D49) C5296_0
(00F89323) _ReThrowException
(000719D7) TEditorManager::CheckFileChange
(0006F9A2) TEditorManager::Check
(00018C78) TCustomScpExplorerForm::Idle
(00049A6F) TNonVisualDataModule::DoIdle
(00049A2C) TNonVisualDataModule::SessionIdleTimerTimer
(003A47E0) System::Classes::_18201
(00043449) USER32.dll
(00023F87) USER32.dll
(000230D9) USER32.dll
(00022EBB) USER32.dll.DispatchMessageW

The problem happens rarely. I cannot reproduce it.