Error listing directory, Invalid access to memory

Hi Martin,

I am using WinSCP 3.6.8 Build 245 on Windows XP Professional (with pretty much default settings). Recently I started seeing error messages after I click on a right-panel Refresh button (for a remote UNIX server):

Error listing directory, Invalid access to memory, Invalid access to memory...

I do not see them every time I click Refresh, just sometimes. I think that the error can happen only after some idle time (idle for WinSCP, not for me). When it happens, the right panel shows the standard animated light.

I made a screenshot that I can send to you if you like.

Thank you,
Vladimir

I'm getting this exact error, also. After some idle time, I hit refresh and repeatedly this box pops up until eventually it crashes. :(

Hi Martin,

That happened once again. Let me describe what I am doing. I am monitoring a remote log file which keeps growing. And I keep downloading that file to my workstation once in a while replacing the old copy. So I always have that file selected (on the right panel). The remote directory contains a lot of files, and the log file is in the middle of the list. To find the file, I have to scroll down. After I click Refresh for the first time the directory list is rearranged so that the selected file is at the very bottom of the panel. And I do not scroll the list any more.

Last time when I got "Invalid access to memory" I was looking at my file while clicking OK. Every single click was changing the file visibility. First, I can see it, then I cannot see it, then I can see it again, and so on.

Thank you,
Vladimir

OK, is some of you able to reproduce the bug on demand? If you are, I will prepare debug version of WinSCP to track down the problem. But if you are not able to reproduce the bug on demand, it is hard to solve this. Please, let me know.

@martin: I get this same Invalid access to memory error whenever I am idle for more than thirty minutes or so, and I try to access files on the server. Could this be caused by an automated session timelimit within the servers SFTP settings?

Hi Martin,

I am not sure if I can reproduce the bug. Today I was working smoothly.

Does your debug version send any information to you automatically or it only writes to a log file, which I can send to you later? I can try to debug if the program does not establish connections to any other servers.

Thank you,
Vladimir

It just generates log file. I'll prepare it and contact you then.

Hi Martin,

I have found that it is simple to reproduce the bug on demand. It happens inevitably when I open two or more instances of WinSCP at the same time (connected to different servers).

Thank you,
Vladimir

Hi Martin,

Yes, that is right. I run one WinSCP instance and connect to a remote server. Then I run another WinSCP instance and connect to another remote server. I do not know if it is important but directory structures are the same on both remote servers. And the right panels are showing the same directories on different servers. Some time later I am clicking Refresh for the second remote server and WinSCP crashes. Every time it crashes it sends exactly 3 error reports to Microsoft.

Thank you,
Vladimir

Thanks for info. I'll contact you in few days.

Hi,

I've been getting the same problem. I've noticed it happens when I am navigating through remote directories and I get a message that the "Host has not answered for more than 15 seconds...".

If I press "Abort", I get the error message "Invalid access to memory" several times until the program eventually crashes.

Most of the time, it seems to happen when I try to open a directory in the "Open Directory" box (Ctrl+O).

I have tried re-installing the software and rebooting the computer, and that might work for a little while, but the problem comes back again out of nowhere.

Has anybody solved this issue?
Thanks,
Sima
p.s. I'm using v3.7.1

@simaazar: It is already fixed and it will be included in the next release. See "Not Released Yet" chapter of version history. If you want I can provide you pre-release version for testing.

I get exactly same error on 3.7.4 build 271

Is not important if you're connected to one or two servers, I have two one with RH7.2 and RH9

On previous versions I never get this error.

Best regards

@Guest: Do you use SFTP or SCP? If SFTP, tell me what is your SFTP server and post a low-level protocol log

Version 3.7.6 (306), NC style, SFTP v.3, Windows 2000

Try to very fast clicking on the Refresh toolbar button (Unix side). For example 20+ times in very short time manner (as soon as your mouse and hand can). It is very probable you see Invalid access to memory after the last click.

@Guest: It does not happen to me. And I've tried hard :-) Can you try 3.8? What OS do you use?

@martin: As I mentioned, I use Windows 2000. When clicking, the list has not been updated completely (that may be a bug prerequisite).

@Guest: All the same but WinXP SP2.

2–3 multiple open sessions, editing files using gvim so long idle times. Even switching between sessions give Invalid memory access errors. As if the sessions shared some memory which they shouldn't.

Really not hard to reproduce, happens every single time I use it.

Hi Martin -
First, thanks for a great program! A guy on my team and I hit this today, and tried some extremes like re-installing, etc. Running the current version 6.1.2. This somehow was effected by performance, including network. He was able to connect to any directory on the server except for one, which has a very large number of folders in it (8027). It does take some time to enumerate (the server is linux and its drive is slow), and he was seeing this error reliably.

He played with Edit > Advanced > Connections > Keepalives --> "Execute Dummy Protocol Commands", until he got a successful read, and somehow that cleared the problem. He had also changed the seconds to keepalive to 29 (timeout -1). Once that worked the problem was gone. I suspect some sort of bad behavior on timeout? Perhaps something not de-allocated or cleared properly?

Hope this helps

@cj: Thanks for your report.
I have sent you an email with a debug version of WinSCP to the address you have used to register on this forum.

Hi Martin, received your email and tried to reply, but that was undeliverable. Permanent error:
smtp; 550 5.7.23 SPF validation failed. : Reason: mechanism

We will attempt to reproduce and try the debug build you sent.

@cj: Thanks. If the email problem persists, please post the log here as a private attachment.