Ran into some access violation in visual studio 2010 and here's the callstack:
Most of the call stack are assembly code in the dll(almost illegible to me). I want to trace back to the line in my code which caused the violation, but it seems there's no user function in the call stack.
How can I find the line in my function causing the violation ? Do I need to adjust some settings ?
Getting a reliable stack trace out of optimized C or C++ code is difficult. The optimizer chooses speed over diagnosability. The debugger needs PDB files for such code to know how to interpret the stack frames correctly and find the return address to the calling method.
Clearly you don't have these PDBs, you are getting the raw addresses from the operating system DLLs instead of their function names. Getting those PDBs is pretty simple, Microsoft has a public server that does nothing but deliver those PDBs for any released version of Windows, including service packs and security updates.
Telling the debugger about that server is required, the feature is off by default. It is particularly easy for VS2010, the server name is preprogrammed in the dialog, you only have to turn it on. Tools + Options, Debugging, Symbols, tick the checkbox in front of "Microsoft Symbol Servers". Set the cache directory, any writable directory will do.
Start debugging again, it will take a while at first to cache the PDBs. When it is done, you'll see a greatly improved stack trace. Accurate and with function names for the Windows DLLs.
Related
I've experienced this with every version of Visual Studio starting from 2012 (2012, 2013, 2015 Preview), on multiple computers and multiple projects, but I haven't figured out how to fix it:
Whenever I'm debugging a 64-bit(?) C++ console program, after a few minutes and seemingly completely randomly (when I'm not clicking or typing anything), the console window for the program spontaneously closes and I can no longer debug or step through the program with Visual Studio. When I press Stop and attempt to restart debugging, I usually get ERROR_NETWORK_UNREACHABLE:
// MessageId: ERROR_NETWORK_UNREACHABLE
// MessageText:
// The network location cannot be reached. For information about network troubleshooting, see Windows Help.
#define ERROR_NETWORK_UNREACHABLE 1231L
If I try to attach to the process manually I get the error:
Unable to attach to the process.
The only fix I've found for this is to restart Visual Studio. I can't find any other way to fix it, and I've tried running Process Monitor but haven't found anything.
What causes this problem and how can I fix it?
(?) Upon further checking it seems that this only happens in 64-bit mode, but I'm not 100% sure.
Ok, this is just so wrong
I also have issues with this bug, and in my case it occurred every other debug session. Which meant debug -> stop -> debug -> bug -> restart visual studio -> go to start (repeat every minute during the whole day).
Needless to say I was driven to find a solution. So yesterday I tried procmon, spend hours looking at API monitor differences, looked at plugins, netstat, etc, etc, etc. And found nothing. I gave up.
Today
Until today.
To track down a stupid bug in my program today, I launched appverifier. For my application, I ran the 'basics' tests and clicked save. After a few hours this led me to the bug in my program, which was something like this (extremely simplified version):
void* dst = _aligned_malloc(4096, 32);
memcpy(dst, src, 8192);
Obviously this is a bug and obviously it needed fixing. I noticed the error after putting a breakpoint on the memcpy line, which was not executed.
After a stop and 'debug' again I was surprised to find that I could actually debug the program for the second time. And now, several hours later, this annoying bug here hasn't re-emerged.
So what appears to be going on
So... apparently data from my program is bleeding through into the data or execution space of the debugger, which in turn appears to generate the bug.
I see you thinking: No, this shouldn't happen... you're right; but apparently it does.
So how to fix it? Basically fixing your program (more particular: heap corruption issues) seems to make the VS debugger bug go away. Using appverifier.exe (It's in Debugging tools for Windows) will give you a head start.
Why this works
Since VS2012, VC++ uses a different way to manage the heap. Hans Passant explains it here: Does msvcrt uses a different heap for allocations since (vs2012/2010/2013) .
What basically happens is that heap corruption will break your debugger. The AppVerifier basic settings will ensure that a breakpoint is triggered just before the application does something to corrupt the heap.
So, what happens now is that before the process will break the heap, a breakpoint will trigger instead, which usually means you will terminate the process. The net effect is that the heap will still be in-tact before you terminate your program, which means that your debugger will still function.
"Test"
Before using appverifier -- bug triggered every 2 minutes
While using appverifier -- VS debugger has been stable for 5 days (and counting)
This is an environmental problem of course. Always hard to troubleshoot, SysInternals' utilities like Process Monitor and Process Explorer are your primary weapons of choice. Some non-intuitive ways that a network error can be generated while debugging:
Starting with VS2012, the C runtime library had a pretty drastic modification that can cause very hard to diagnose mis-behavior if your program corrupts the heap. Much like #atlaste describes. Since time memorial, the CRT always created its own heap, underlying call was HeapCreate(). No more, it now uses GetProcessHeap(). This is very convenient, much easier now to deal with DLLs that were built with /MT. But with a pretty sharp edge, you can now easily corrupt the memory owned by Microsoft code. Not strongly indicated if you can't reattach a 64-bit program, you'd have to kill msvsmon.exe to clear up the corruption.
The Microsoft Symbol Server supplies PDBs for Microsoft executables. They normally have their source+line-number info stripped, but not all of them. Notably not for the CRT for example. Those PDBs were built on a build server owned by DevDiv in Redmond that had the source code on the F: drive. A few around that were built from the E: drive, Patterns+Practices uses that (unlikely in a C++ program). Your debugger will go look there to try to find source code. That usually ends well, it gives up quickly, but not if your machine uses those drive letters as well. Diagnose by clearing the symbol cache and disabling the symbol server with Tools + Options, Debugging, Symbols.
The winapi suffers from two nasty viral infections it inherited from another OS that add global state to any process. The PATH environmental variable and the default working directory. Use Control Panel + System + Advanced + Environment to have a look at PATH, copy/paste the content of the intentionally small textboxes into a text editor. Make sure it is squeaky clean, some paralysis at the usual mess is normal btw. Take no prisoners. Having trouble with the default directory is much harder to troubleshoot. Both should pop out when you use Process Monitor.
No slamdunk explanations, it is a tough problem, but dark corners you can look in.
I have the same problem. Thought it was related to 64 bit console apps, where it is very easily triggered with almost any debug session. But, it also happens on 64 bit windows apps too. Now I am seeing it on 32 bit windows apps. I am running Windows 8.1 pro on a single desktop with the latest version of vs 2013 and no remote debugging. My (added) extensions are Visual Assist, Advanced Installer, ClangFormat, Code Alignment, Code Compare, Duplicate Selection, Productivity Power Tools 2013, and Visual SVN.
I discovered that the "Visual Studio 2013\Settings\CurrentSettings.vssettings" file gets corrupted. You can delete this file and recreate it by restarting VS or you can try to edit the XML. I then keep a copy of a good settings file that I use to replace when it gets corrupted again.
In my case, the corrupted line begins with
</ToolsOptionsSubCategory><ToolsOptionsSubCategory name="XAML" RegisteredName="XAML"
... and it is extremely long (I think this is why it is prone to corruption).
I just disabled in the Menu
Tools > Options
Debugging > Edit and Continue
Native-only options > Enable native Edit and Continue
and now it does not give the that stupid error which was preventing the starting of the debuggee application.
I also had the same problem with VS2015. It was so frustrating that a simple Hello World program gave this error when I ran debugger for the second time. Tried uninstall and reinstall and didn't work.
Finally, the solution mentioned in https://social.msdn.microsoft.com/Forums/vstudio/en-US/8dce0952-234f-4c18-a71a-1d614b44f256/visual-studios-2012-cannot-findlaunch-project-exe?forum=vsdebug
worked. Reset all visual studio settings using Tools->Import and Export settings. Now the issue is not occurring.
I tried to catch the stack trace of an address, but it always show me nothing,
my issue is analyse memory leak, so i have queried all heap statics and then queried highest allocated memory, it returned me lot of allocation,
and i tried to search many of allocation address by “!heap -p –a ####“, #### is adress.
but it never return me any call stack,
but if I search this address/any other adresses in memory, it shows me similar allocation.
also if i try to run this command “dt ntdll!_DPH_HEAP_BLOCK StackTrace ####,” , it return me NULL stack trace.
is it because of page heap for application is not enabled????
For native memory issues, you cannot easily use dumps to determine the root cause.
Microsoft has a tool DebugDiag for 32 bit processes,
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=28bd5941-c458-46f1-b24d-f60151d875a3&displaylang=en
You can use it to track native memory leaks in some typical scenarios,
http://support.microsoft.com/kb/919790
Besides, involving Microsoft support team can speed up the root cause analysis,
http://support.microsoft.com
There are a number of things here, firstly you will not get a complete stack trace for symbols you do not have access to, for this you need the pdbs without the private symbols stripped.
For the microsoft symbols entering '.symfix;.reload' in WinDbg should fix that problem.
Secondly although you will not get a stack trace for 3rd party dlls you will for your own application dlls, you will need to make sure your pdbs with public symbols match the version used to generate the dump.
You could ask the customer to generate the user stack trace in gflags and reproduce the error or to send you the pdbs with full symbol information.
It is also possible to open the dump file in Visual studio:
File->Open->Project/Solution navigate to dump file and click ‘OK’
In Solution Explorer right click project->Debug->Start new instance
You may find this approach more familiar but you will not have access to WinDbg tools but as this is a post mortem analysis you can open the dump in visual studio and WinDbg as you are not invasively debugging anyway.
Here's the situation:
Background
I have a mixed mode .NET/Native application developed in Visual Studio 2008.
What I mean by mixed mode is that the front end is written in C++ .NET which calls into a native C++ library. The native code does the bulk of the work in the app, including kicking off new threads as it requires. The .NET code is just for UI purposes (win forms).
I have a release build of application running on a tester's computer.
The native libraries were compiled with full optimisations but also with debugging enabled (the "Debug Information Format" was set to "Program Database").
What this means is that I have the debugging symbols for the application in a PDB file.
The problem
So anyway, one of the testers is having a problem with the app where it occasionally crashes on XP. I've been able to get the minidump of the crash using Dr Watson for several runs.
When I debug into it (using the minidump - I'm not actually debugging the real app), all the debugging symbols are loaded correctly: I can see the full stack trace of all of the native threads correctly. Other threads (which are presumably the .NET threads) don't have a stack trace, but they all at least show me which dll the thread was started on (i.e. ntdll.dll).
It correctly reports the thread which fails ("Unhandled exception at 0x0563d652 in user(5).dmp: 0xC0000005: Access violation reading location 0x00000000).
However when I go into the thread it shows nothing useful. In the stack trace there is a single entry which just has the memory address "0563d652()" (not even "ntldll.dll").
When I go into dissasembly it just shows a random section of about 30 instructions. Either side of the memory address is just "???". It almost looks like it is not part of my source code (isn't your binary loaded sequentially into memory? is it normal to have a random set of assembly statements in the middle of nowhere?).
My questions
So basically my questions are threfold.
1) Can anyone explain the debugger's lack of information?
2) Bearing in mind, I can't show the error occurred in my code, can anyone suggest a reason for the failure
3) Can I do anything else to help me diagnose this current problem in the future?
Help!
John
Update:
Here is the stack dump for the failing thread from WinDBG
# ChildEBP RetAddr
WARNING: Frame IP not in any known module. Following frames may be wrong.
00 099bf414 02d0e7fc 0x563d652
01 00000000 00000000 0x2d0e7fc
Weird huh? Doesn't even show a DLL.
Is it possible that I've corrupted the stack/heap somehow which has caused a thread to just get corrupted...?
Are you using WinDbg? If so, are you using the Son of strike extension?
Bugslayer: Son-of-Strike
-or-
Drill Into .NET Framework Internals to See How the CLR Creates Runtime Objects?
We had an issue similar to this where a code bug was silent in MSVC2K5 SP1, but if you had the MSVC2K5 SP2 runtime installed it caused an error which didn't point at valid code.
Part of the problem is, when you start executing data as code you could be doing anything and so the crash location becomes useless as you cannot even get back to a valid stack trace.
We had this happen to us when the new .Net runtime install installed a newer version of the MSVC C++ Runtime in the SxS directory.
In the end our method to resolve the issue was to make the crash happen frequently and add as much logging as necessary to localize it.
could you post the stack of the faulting thread once you've grabbed and installed a copy of windbg and opened the dump file there?
we could start from there.
Your EIP was just corrupted.
Assuming the ESP is valid, you can view the callstack, just type:
dds esp [enter]
dds [enter]
You can also use the memory windows:
Set address to: esp
Set format to: Pointer&Symbol
If my C++ app crashes on Windows I want to send useful debugging information to our server.
On Linux I would use the GNU backtrace() function - is there an equivalent for Windows?
Is there a way to extract useful debugging information after a program has crashed? Or only from within the process?
(Advice along the lines of "test you app so it doesn't crash" is not helpful! - all non-trivial programs will have bugs)
The function Stackwalk64 can be used to snap a stack trace on Windows.
If you intend to use this function, you should be sure to compile your code with FPO disabled - without symbols, StackWalk64 won't be able to properly walk FPO'd frames.
You can get some code running in process at the time of the crash via a top-level __try/__except block by calling SetUnhandledExceptionFilter. This is a bit unreliable since it requires you to have code running inside a crashed process.
Alternatively, you can just the built-in Windows Error Reporting to collect crash data. This is more reliable, since it doesn't require you to add code running inside the compromised, crashed process. The only cost is to get a code-signing certificate, since you must submit a signed binary to the service. https://sysdev.microsoft.com/en-US/Hardware/signup/ has more details.
You can use the Windows API call MiniDumpWriteDump if you wish to roll your own code. Both Windows XP and Vist automate this process and you can sign up at https://winqual.microsoft.com to gain access to the error reports.
Also check out http://kb.mozillazine.org/Breakpad and http://www.codeproject.com/KB/debug/crash_report.aspx for other solutions.
This website provides quite a detailed overview of stack retrieval on Win32 after a C++ exception:
http://www.eptacom.net/pubblicazioni/pub_eng/except.html
Of course, this will only work from within the process, so if the process gets terminated or crashes to the point where it terminates before that code is run, it won't work.
Generate a minidump file. You can then load it up in windbg or Visual Studio and inspect the entire stack where the crash occurred.
Here's a good place to start reading.
Its quite simple to dump the current stackframe addresses into a log file. All you have to do is get such a function called on program faults (i.e. a interrupt handler in Windows) or asserts. This can be done at released versions as well. The log file then can be matched with a map file resulting in a call stack with function names.
I published a article about this some years ago.
See http://www.ddj.com/architect/185300443
Let me describe how I handle crashes in my C++/WTL application.
First, in the main function, I call _set_se_translator, and pass in a function that will throw a C++ exception instead of using structured windows exceptions. This function gets an error code, for which you can get a Windows error message via FormatMessage, and a PEXCEPTION_POINTERS argument, which you can use to write a minidump (code here). You can also check the exception code for certain "meltdown" errors that you should just bail from, like EXCEPTION_NONCONTINUABLE_EXCEPTION or EXCEPTION_STACK_OVERFLOW :) (If it's recoverable, I prompt the user to email me this minidump file.)
The minidump file itself can be opened in Visual Studio like a normal project, and providing you've created a .pdb file for your executable, you can run the project and it'll jump to the exact location of the crash, together with the call stack and registers, which can be examined from the debugger.
If you want to grab a callstack (plus other good info) for a runtime crash, on a release build even on site, then you need to set up Dr Watson (run DrWtsn32.exe). If you check the 'generate crash dumps' option, when an app crashes, it'll write a mini dump file to the path specified (called user.dmp).
You can take this, combine it with the symbols you created when you built your server (set this in your compiler/linker to generate pdb files - keep these safe at home, you use them to match the dump so they can work out the source where the crash occurred)
Get yourself windbg, open it and use the menu option to 'load crash dump'. Once it's loaded everything you can type '~#kp' to get a callstack for every thread (or click the button at the top for the current thread).
There's good articles to know how to do this all over the web, This one is my favourite, and you'll want to read this to get an understanding of how to helpyourself manage the symbols really easily.
You will have to set up a dump generation framework in your application, here is how you may do it.
You may then upload the dump file to the server for further analysis using dump analyzers like windbg.
You may want to use adplus to capture the crash callstack.
You can download and install Debugging tools for Windows.
Usage of adplus is mentioned here:
Adplus usage
This creates the complete crash or hang dump. Once you have the dump, Windbg comes to the rescue. Map the correct pdbs and symbols and you are all set to analyze the dump. To start with use the command "!analyze -v"
Sometimes my c++ program crashes in debug mode, and what I got is a message box saying that an assertion failed in some of the internal memory management routines (accessing unallocated memory etc.). But I don't know where that was called from, because I didn't get any stack trace. How do I get a stack trace or at least see where it fails in my code (instead of library/ built-in routines)?
If you have a crash, you can get information about where the crash happened whether you have a debug or a release build. And you can see the call stack even if you are on a computer that does not have the source code.
To do this you need to use the PDB file that was built with your EXE. Put the PDB file inside the same directory as the EXE that crashed. Note: Even if you have the same source code, building twice and using the first EXE and the second PDB won't work. You need to use the exact PDB that was built with your EXE.
Then attach a debugger to the process that crashed. Example: windbg or VS.
Then simply checkout your call stack, while also having your threads window open. You will have to select the thread that crashed and check on the callstack for that thread. Each thread has a different call stack.
If you already have your VS debugger attached, it will automatically go to the source code that is causing the crash for you.
If the crash is happening inside a library you are using that you don't have the PDB for. There is nothing you can do.
If you run the debug version on a machine with VS, it should offer to bring it up and let you see the stack trace.
The problem is that the real problem is not on the call stack any more. If you free a pointer twice, that can result in this problem somewhere else unrelated to the program (the next time anything accesses the heap datastructures)
I wrote this blog on some tips for getting the problem to show up in the call stack so you can figure out what is going on.
http://www.atalasoft.com/cs/blogs/loufranco/archive/2007/02/06/6-_2200_Pointers_2200_-on-Debugging-Unmanaged-Code.aspx
The best tip is to use the gflags utility to make pointer issues cause immediate problems.
You can trigger a mini-dump by setting a handler for uncaught exceptions. Here's an article that explains all about minidumps
Google actually implemented their own open source crash handler called BreakPad, which also mozilla use I think (that's if you want something more serious - a rich and robust crash handler).
If I remember correctly that message box should have a button which says 'retry'. This should then break the program (in the debugger) at the point where the assertion happened.
CrashFinder can help you locate the place of the exception given the DLL and the address of the exception reported.
You can take this code and integrate it into your application to have a stack trage automatically generated when there is an uncaught exception. This is generally performed using __try{} __except{} or with a call to SetUnhandledExceptionFilter which allows you to specify a callback to all unhandled exceptions.
You can also have a post-mortem debugger installed on the client system. This is a decent, general way to get information when you do not have dump creation built into your application (maybe for an older version for which you must still get information).
Dr. Watson on Windows can be installed by running: drwtsn32 -i Running drwtsn32 (without any options) will bring up the configuration dialog. This will allow the creation of crash dump files, which you can later analyze with WinDbg or something similar.
You can use Poppy for this. You just sprinkle some macros across your code and it will gather the stack trace, together with the actual parameter values, local variables, loop counters, etc. It is very lightweight so it can be left in the release build to gather this information from crashes on end-user machines