I have a web application, which in the course of a normal interaction, hangs IE. By "IE being hung", I mean that IE doesn't respond anymore and using 100% of the CPU. The only to get out of this state is to kill the IE process. About the app:
It loads only one page in the browser, communicates with a server with Ajax queries, and updates the DOM.
I can reproduce this with both IE6 and IE7, but not Firefox or Safari.
I am wondering if anyone has seen this already, and if there are a few known cases that can get IE into this hung / using 100% of the CPU state.
Use WinDbg, http://www.microsoft.com/whdc/devtools/debugging/
Attach it to the IE process that has the problem.
The .symfix+ command will set your symbol path to point to the Microsoft symbol server and cache the debug symbols locally.
The !runaway command will enumerate all the stacks in the process and tell you which one is going berserk.
If you're lucky, you may see something recognizable, such as a regex replacement at the top of the stack. Or perhaps the layout engine has gone into an infinite loop. Both of these have happened to me in the past.
If the callstack doesn't make sense, use 'g' to make the process go, wait a few seconds, hit Ctrl+Break, then try !runaway again.
Once you've got the symbols locally, you can also use SysInternals' Process Explorer to look at a process's stacks. Configure the Symbols option in Process Explorer to point to your local symbol cache, something like c:\Program Files\Debugging Tools for Windows\sym.
Try attaching the script debugger (via Visual Studio, in my case), and see what is causing it.
Most likely it's a javascript running an infinite loop, or just looping too fast for what needs to be done per ajax request.
Have you tried tracing the problem? If the problem also happens in IE8 you could use console.log commands and their awesome new debugger/dev tool that's built in. Otherwise use the old dev toolbar for IE or alerts. Try to reduce the problem and then file a bug (and paste the code here please).
Related
I have a VB6 application that I provide support for. This application works on both Windows XP and Windows 7. Some users were migrated from Windows XP to Windows 7 using the User State Migration tool. These users now receive a generic "Application has crashed" Windows error message when they open certain screens (forms) in the application. My assumption is that there is a missing dll/ocx reference, but I'm having trouble tracking it down.
I've tried many/varied troubleshooting techniques:
Full uninstall and reinstall of my application
Manually re-registering all dll's and ocx's that I know are used
Running Process Monitor on a broken computer and a working computer to compare what dll's and ocx's are accessed. The answer might be here but even after filtering out most of the background noise the amount of data is overwhelming. At a minimum I reviewed all of the calls right before it crashes and all of the calls that were not successful. All of the non-successful calls match between working and non-working.
Installed the Windows Debugger Tools and captured a crash dump. Analyzed the crash dump with DebugDiag. DebugDiag says the exception is in msvbvm60.dll. I tried building a PDB file for my exe and loading it in DebugDiag to get more detail about where the exception is occuring but DebugDiag doesn't want to accept the PDB (might be doing something wrong here, but it just seems to ignore it. This same PDB file works fine when I do remote debugging, however.)
I recompiled my VB6 program without any optimizations in PCode. I've read online that sometimes building in PCode, while bad for performance, will tell you the real exception.
Used the above created PDB file to remote debug the VB6 application. The debugger says that the application crashes after the new window has been created, on a line that sets MousePointer = vbHourGlass... To me it seems unlikely that this is the real cause of the error. There are at least 20 other locations in the program where this same line is called and all work fine.
(Forgot about this one)
Used Dependency Walker and profiled the application on both a working and non-working computer. All errors found by dependency walker were the same between the two computers. There were no additional dependencies found on a working computer, and all missing dependencies on the non-working computer were also missing on the working one.
None of these actions changed my error message or showed me what the error is (unless it really is the mouse cursor issue)... There are no entries in the Windows Event Log related to the app crash.
The non-working and working computers all have the same base Windows 7 image, the only difference is whatever is being changed by USMT, which further convinces me that this is some kind of quirky configuration change or a missing dll/ocx or perhaps an unregistered dll/ocx.
Any ideas or thoughts on how I can track down the root cause of the issue would be greatly appreciated.
Update 1 - Response to questions
#MarkHall I have tried running it as admin, though not with UAC off. The application runs fine on a Windows 7 box as a non-admin with full UAC. Windows XP was 32-bit, Windows 7 is 64-bit, but again it works just fine on a like for like box where the user was not migrated from Windows XP.
#Beaner It's possible that it stores settings somewhere that have been corrupted, but the remote debugging leads me to think that it's more likely something else since it seems to die on a step related to the UI, which then makes me think it's probably a missing dll/ocx reference.
#Bob77 The application is installed into Program Files (x86). While many of the libraries do reside in the same folder, they are all registered.
Peter, often I've noticed that the debugger will indicate a line of code that is actually incorrect, depending on WHERE in the actual assembly language the fault occurs. You should look REAL close around your statement that sets the cursor to vbHourGlass. Your exception is PROBABLY happening BEFORE that line of code, but that line is what the debugger thinks is the actual faulted line of code.
Since you said it happens when a window OPENS, I'd look real close at any ocx's you may have referenced on the form, but perhaps NOT actually being used, or called. You might have one there that you don't intend to be there, that could be causing security issues, or something on Win7? Edit the .frm file by hand if you have to, and look at all the GUIDs the form references.
It is possible that one machine is using PER-USER registration, and the other is using PER-SYSTEM registration?? I don't know...
I would take a much closer look at the form that you are trying to open, and be VERY cautious of everything you are doing in the form load events, and so on. This sounds like it could be something as stupid as Windows Aero being enabled on one system, and not another, or some other sort of "Theme" setting that is throwing the VB Form Rendering routine into a hissyfit... Perhaps even something as stupid as a transparent color index in the icon you selected for that from?
If you are still developing this app, (or at least maintaining it), create an entirely NEW form, and re-create all the controls, etc, on the form (resist the temptation to copy/paste them from the old one...), and then see if THAT does the trick. Then, copy all the event code to the new form one event at a time, with at LEAST enough event code to make the form function, even if it's just a "dead form", that loads no data, or whatever the form is supposed to do. Check and debug after each change, and you WILL find it eventually. Of course, make sure you isolate one of the defunct systems to have a platform that you can duplicate the issue on, or then it's just guessing. I find that using something like Acronis w/ Universal Restore is a great option to then take the image file into a good HV, like VirtualBox, and then restore that image as a VM, so you can debug without interfering with your actual users. This sounds like a lot of work, but then again, so is re-writing an application that already exists, right? :)
Failing THAT... /* and */ are your friends!! (Well, we're dealing with VB, so ' would be your best friend! heh... But I'd start commenting out all the code on the form until that sucker opens. Then once it opens, start putting one line back at a time, and re-running it... That's called "VooDoo Debugging", but sometimes, you gotta do what you gotta do...
THANKS A LOT PETER! :) Now you got ME so involved in this, I feel like I'M the one debugging this sucker! Like if it was MY code I was trying to fix! :)
Let me know if any of this helps... I am actually quite interested in what you discover.
I have a VS2010 web project that I debug with iisexpress.
Sometimes when stepping code I notice something wrong that would have undesirable effects, e.g. in my 70 Gigabyte database, so I want to stop the code.
My reflex action is to stop debugging in VS2010, but this has the effect that the debugger detaches from the process, and that causes the code to continue running at full speed and do that thing I wanted to avoid.
So, is there any way to get the site to stop instead of continue running at full speed, when I stop debugging in VS?
Note: I don't lose any data or anything - it's safe test data. But due to the large database size, restoring a new test database is a big waste of time.
Note 2: I know I can stop iisexpress in various ways instead of stoppping the debugger in VS. The problem is that I keep forgetting this, and remember only after the damage is done.
So, please, no suggestions that tell med how to stop iisexpress manually or how to protect my database. Only try to answer the actual question: how to AUTOMATICALLY stop the site from executing when I hit "stop debugging" inside VS. That's it.
Other than with a third party or otherwise bespoke program (or script configured to run on debugger attachment (?)), let me disregard your demand to only answer the question exactly and provide another thought at least...
In an emergency, step through the code with the debugger and upon noticing the potential detriment manually move the execution scope to, say the end of the method, essentially skipping the code you don't want to run.
So, say if a page does something in the load event, move to the closing brace of the event handler code and then continue, the page will load minus the code having been executed.
I'm currently learning OpenGL and I've noticed a rarely occuring performance problem:
My program is rather small so it's not a performance problem with the code itself, but when I'm running the code via Visual Studio I sometimes only get 1-2 FPS instead of the usual 60.
Once this happens I can restart the program as often as I want to (in debug and release mode alike) and it won't go away.
However, when I close my Firefox (or manually shut down the plugin-container.exe though task manager) and restart my program everything is fine again. After that I can start Firefox again (with the same tabs open) and the bug does not reappear.
I use the newest version of Firefox, and I've had this bug with several programs already - both made by me and others and using different versions of OpenGL. However I don't think I've had this problem when starting a compiled exe directly, but only by using the Run feature of Visual Studio.
I've searched the web but I only found a link about the generally bad performance of this plugin-container.
Does anyone else have this problem? Do you know any walkarounds or fixes?
PS: Regarding isti_spl's answer:
The CPU utilisation of the plugin-container.exe jumps to the 50% limit when the problem happens.
I'm working with Visual Studio, but the problem only occurs when I also have Firefox running (it most certainly is because of this plugin-container, so it probably won't happen with other browsers).
It's hard to isolate the problem because I can't replicate it. It might happen 1 out of 50 times.
I'll see if closing flash-related tabs (youtube, blip.tv etc) fixes the problem next time it happens.
Can you isolate the problem?
You first mentioned running visual studio then firefox. Please try to run separately.
Under FF. is it caused by WebGL or flash plugin? Is it caused by visiting specific sites?
Is it FF specific or happens under other browsers too?
Does CPU utilisation jump high? Please verify that too and which process consumes most CPU.
Not sure, but likely gpu driver + flash problems.
If so, the problem is not in your code, other GL program should be affected too.
I'm running a test script from batch file.
Because it is test, the programs are expected to fail once in a while. It is file as long as error code is returned so I can continue and mark specific test as failed.
However there is very annoying behavior of executable files under Microsoft Windows - if something fails it pop-ups window like:
This application has failed to start because foo.dll was not found, Re-installing the application may fix the problem
<OK>
Or even better:
The instruction at "..." referenced to memory at "..." ..
Click on OK to terminate the program
Click on CANCEL to debug the program
The result is known - the script execution blocks till somebody presses "Ok" button. And when we talk about automatic scripts that may run automatically at night in some headless virtual machine, it may be very problematic.
Is there a simple way to prevent such behavior and just make an application to exit with failure code - without changing the code of the program itself?
Is this possible at all?
The answer is following: You need to disable WER.
Simplest description for this I found at http://www.noktec.be/archives/259
Simply (ON XP): Right Click on My Computer > Advanced > Error Reporting > Disable
Voila - programs crash silently!
This does not solves problem when DLL is missing, but this is much rare case and this is good enough for me.
You can suppress AV's and such from showing a dialog box by running your application, or the script (the script engine, like cscript.exe), under a debugger.
Use Gflags.exe, or modify the registry directly, and set Image File Execution Options for the image in question. See this article for details on how to use the appropriate registry keys. You can set it up using a debugger commandline like "C:\Debuggers\ntsd.exe -g -G -c'command'", where you can pass commands to ignore certain types of exceptions in the -c"commmand" argument. This will effectively give you a tool to suppress interactive dialogs as a result of exceptions like AV, and will let the process continue (presumably to immediate end after the exception has occured).
This article explains the commands you can use to control exceptions and events from withing the debugger.
The -g and -G flags make sure that the process won't break into the debugger automatically during process start and end respectively. You'll have to play with the various exception suppression options to make sure that you 'eat' all possible first and second chance exceptiosn that might cause the process to break into the debugger.
Also, if you can tolerate a process being broken into the debugger (as against being stuck showing a dialog box), perhaps that would be a better option overall. You can evaluate each debug break in batch mode at a later time and decide which bugs you care to fix.
It is possible. We used to use IBM's Rational Robot product which could monitor the screen for specific items and, if found, send keystrokes to windows and other sorts of things.
We actually used it for fully automated unit and system testing, much like you're trying to do.
Now I thought that Robot has been through quite a few name changes so it may be hard to find but there it is, right on IBM's web page and with a free downloadable trial for you. It's not cheap, clocking in at a smidgeon under USD5,000 but it was worth it for us.
There's also TestComplete where you could get a licence for just unedr USD1,000 - it touts "Black-box testing - Functional testing of any Windows application" as one of its features and also has a downloadable demo to see if it's suitable before purchase.
However, you may be able to find another product to do the same sort of thing.
I initially thought of Expect but the ActiveState one seems to concentrate on console applications which leads me to believe it may not do graphics well.
The only other option I can suggest is to write your own program in VBScript. I've done this before to automate the starting of many processes (log on to work VPN, start mail, log in and so on) so I could be fully set up with one mouseclick instead of having to start everything manually.
You can use AppActivate to bring a window to the foreground and SendKeys to send arbitrary keypresses to it after that. It's possible you may be able to cobble together something from that if you want a cheaper solution.
We've been plagued for several years by occasional reports from customers about a non-descript error message "Cannot set allocations" that appears on startup of our app. We have never been able to reproduce the problem in our own test environments so far. I have now run out of ideas for attempting to track this down. Here's a collection of observations that have accumulated over time:
Error message text reads "Cannot set allocations" (note absence of punctuation).
The window title simply reads "Error" (or the localized equivalent).
The "Cannot set allocations" text is always in English regardless of OS locale.
I have so far not been able to locate the DLL or EXE containing the message text.
Google is chock full of reports of this error for a variety of different products - but no solutions.
The only unifying aspect between the affected products I could make out so far was that they all appear to come in the form of DLLs that load into third-party processes (such as addins for Visual Studio or Windows Explorer shell extensions).
Our app is actually a shareware COM-addin for MS Outlook, written in Delphi (i.e. native code - no .NET).
The prime suspect in our case is the third-party licensing wrapper that we're using which decrypts and uncompresses our DLL into memory on the fly. Obviously I couldn't simply give an unprotected version of our app to the affected customers to verify this suspicion. Maybe the other vendors that this has been reported against are using similar products.
Debug versions of the protection wrapper supplied to us by the licensing vendor yielded no results: The log files looked exactly the same as from sessions where the error did not occur. Apparently the "inner" DLL gets decrypted and uncompressed all right but for some reason still fails to get loaded by the host process.
By creating an unprotected "loader" DLL we have been able to pinpoint the occurrence of the error somewhere behind the LoadLibrary call that is supposed to load our DLL into memory.
Extensive logging and global exception hooks in our own code (both the unprotected loader and the protected "core"-DLL) yielded no results at all. The error is obviously raised somewhere else.
The problem described in this earlier question of mine was very probably prompted by the same issue. This was before we created the unprotected loader stub.
The error only occurs at about 1-2% of our customers - whereas typically all installations at any affected customer's site are affected the same.
Sometimes the error goes away after we release a new version but often it will come back again after a couple of weeks or months.
Once the error has started to occur on a machine it does so consistently.
The error never occurs while connected to the affected machine via remote access (e.g. VNC, RDP, TeamViewer, etc.) and none of the affected customers are within travel distance from us so all we have to go by is log files and "eye-witness reports".
One customer reported that the error message dialog apparently was non-modal, i.e. he was able to simply move the dialog box to the side and continue working with the application (minus the functionality that our DLL would have provided). Not sure whether this is universally true in all other occurrences, too.
In some cases customers have been able to permanently rid themselves of the error by disabling or uninstalling other addins from other vendors that were sharing the host application with our own product.
The error has so far been observed on Windows XP, Vista and 7.
During the last few weeks we had a surge of reports from Outlook 2003 / Windows 7 users. Could the situation have been made worse by a recent Windows/Office-update?
Does anyone have any experience with this error at all?
Or any more ideas for investigating this?
I have only recently had this happen, which prompted my search and I ended up here. I can tell you that with me for sure it is in windows 7 home premium BUT ONLY WITH IE9 (which I hate by the way) it reduces the user back to the dummy stage and assumes that we have to be repeated flagged about everything.It will keep asking you if you want to disable add ons to speed up load times but usually on things that aren't really the things slowing the browser down in the first place,it is there is too much garbage loading in the first place.But back to the "Cannot set allocations", I for one have never expirianced it in any other browser which is not to say it doesn't happen with them.
This is going to be pure guess-work, but it sounds like maybe your third-party licensing software is trying to load your DLL at a particular location in memory, which - on these failing systems - happens to already be occupied by something else, perhaps a global hook DLL.
If you have a customer who is willing to work with you a bit, it might shed some light on the situation to get a crash dump (e.g., with ADPlus or maybe simpler with Sysinternals' ProcDump) when the error message is showing. That would show what modules are loaded and possibly the callstack (if it is from a message box at the time of the error as opposed to one that is catching an exception after the problem).
I also have experienced the "Cannot set allocations" issue. Royal pain. I had disabled Java, since I did not seem to need it, I used add/remove programs to remove Java from my system. Then I stated to get those errors. I have reinstalled, but disabled Java in IE explorer. Now I do not get the error anymore. Not a programmer, don't know why this happened. Maybe a clue for someone.
Win 7 - 64bit OS IE Explorer 10. Hope this helps someone figure this out. John
I've seen this happen. In my case a global hook dll created a large memory file mapping, perhaps to the memory the licensing dll was counting on.
I see "Cannot set Allocations" when I open google chrome only. Also after that, chrome closes with a msg saying "Whoa chrome has crashed..."
Still no solution :(
Also not a programmer, but it always happens when I open Chrome. It opens second window with error message 'cannot set allocation'. I usually close it and go on my way. if i don't it usually causes a crash. doesnt happen on any other browsers.