Develop Reference

Examining a managed exception in an unmanaged thread

I'm looking into a mini-dump file where the main thread (c++) utilized CLR to launch a managed (C#.NET) window, an exception was thrown in the managed portion, and crashed the application. I've been searching around looking at techniques to examine an exception details for clues, however they're mainly for one or the other (an entirely unmanaged stack & thread or an entirely managed stack & thread).
The portion of the managed callstack is below, where I can see an exception was raised inside the .NET portion, but I'm not really sure of a method to digging into viewing the details of what was raised. I'm still fairly new at digging through a .dmp file, so any guidance is greatly appreciated.
001ddb04 68b92a42 KERNELBASE!RaiseException+0x58
001ddba8 68c655ef clr!RaiseTheExceptionInternalOnly+0x276
001ddbd8 68c6de52 clr!UnwindAndContinueRethrowHelperAfterCatch+0x83
001ddc6c 627528df clr!CEEInfo::resolveToken+0x59b
001ddc7c 62778872 clrjit!Compiler::impResolveToken+0x3a
001de3ac 62751d53 clrjit!Compiler::impImportBlockCode+0x29b3
001de42c 62751f48 clrjit!Compiler::impImportBlock+0x5f
001de444 62753405 clrjit!Compiler::impImport+0x235
001de464 62753635 clrjit!Compiler::compCompile+0x63
001de4a0 62753823 clrjit!Compiler::compCompileHelper+0x2fa
001de518 627536f6 clrjit!Compiler::compCompile+0x213
001de608 6275385f clrjit!jitNativeCode+0x1e3
001de62c 68a74710 clrjit!CILJit::compileMethod+0x25
001de67c 68a747a9 clr!invokeCompileMethodHelper+0x41
001de6bc 68a747eb clr!invokeCompileMethod+0x31
001de720 68a73684 clr!CallCompileMethodWithSEHWrapper+0x2a
001deab8 68a73920 clr!UnsafeJitFunction+0x3ca
001deb94 68a81e5e clr!MethodDesc::MakeJitWorker+0x36b
001dec08 68a550b6 clr!MethodDesc::DoPrestub+0x59d
001dec70 68a44279 clr!PreStubWorker+0xed
001deca0 16c5185a clr!ThePreStub+0x16
001deda4 5ae8f887 0x16c5185a
001dedc0 5ae20c9c MYDLL!CLoader::InvokeCSharpControl

0x16c5185a is an address in memory where the .NET code has been compiled by the JIT compiler. Due to the just-in-time compilation, there's no symbol like in C++ and you need different tools (extensions for WinDbg).
First, check if it's a .NET exception with .exr -1. Except for a few exceptions, the code should be 0xE0434F4D (.COM in ASCII characters).
If that's the case, load the SOS extension to analyze the .NET details: .loadby sos clr. Next, run the command !PrintException (!pe in short) to get details about the exception and !ClrStack (casing is not relevant) to get details about the .NET call stack.
There may be more details available if you have a good crash dump for .NET.

How can I circument the "80004005 There is a file sharing violation...." err msg on a SQL Server CE database?

I am getting error
80004005 There is a file sharing violation. A different process might be using the file.
when trying to open a SqlCeConnection.
Is there a way to close a SQL Server CE database programmatically, to try to nip that problem in the bud? Something like (pseudocode):
SqlCeDatabase SQLCeDb = "\My Documents\HHSDB003.sdf";
if (SQLCeDb.IsOpen)
{
SQLCeDb.Close();
}
?
Or a way to set the connection so that it doesn't care if the database is open elsewhere/wise, such as:
SqlCeConnection conn = new SqlCeConnection(#"Data Source=\My Documents\HHSDB003.sdf;File Mode = 'shared read'");
...or:
SqlCeConnection conn = new SqlCeConnection(#"Data Source=\My Documents\HHSDB003.sdf;File Mode = 'read write'");
I can't test these at present, because I'm back to getting
Cannot copy HHS.exe The device has either stopped responding or has been disconnected
when I attempt to copy over a new version of the .exe to the handheld.
If there's something more frustrating to program against (and "against" is the correct word here, I think) than the prehistoric versions of Windows CE / Compact Framework / .NET, I'm not at all sure I want to know what it is.
UPDATE
Adding to my frustrusion (haywire combination of confusion and frustration), I found the following at http://www.pocketpcfaq.com/faqs/activesync/exchange_errors.php:
0x80004005 N/A Synchronization failed due to a device software error. Contact your network administrator.
1. Obtain the latest Pocket PC End User Update from your service provider.
UPDATE 2
Is this possibly problematic (than all but the first setting is blank):
UPDATE 3
With this code:
private void menuItemTestSendingXML_Click(object sender, System.EventArgs e)
{
string connStr = "Data Source=My Documents\\HHSDB003.SDF";
SqlCeConnection conn = null;
try
{
try
{
conn = new SqlCeConnection(connStr);
conn.Open();
MessageBox.Show("it must have opened okay");
}
finally
{
conn.Close();
}
}
catch (Exception ex)
{
if (null == ex.InnerException)
{
MessageBox.Show("inner Ex is null");
}
MessageBox.Show(String.Format("msg is {0}", ex.Message));
}
}
...I am now seeing "it must have opened okay" (that's a good thing, but...why it's now working, I have no idea, because the code has not changed since I last ran it and it failed. Something beyond the code must have been at play.
The only thing I can think of that happened that MAY have had a bearing on this change is that, thinking there may have been a rogue instance of either the .exe or its ancillary dll in memory on the handheld device, I wrote an quick-and-dirty utility that looped through the running processes, looking for them and, if finding them, killing them, but they were not there, so the utility really did "nothing" (maybe the Hawthorne effect?).
That is the way working with this combination of tools and technologies seems to go, though: everything is working fine one minute and the next, BAM! It no longer is. Then the reverse can also happen: for no apparent reason it seems to "heal itself".
In the interests of "full disclosure," here is the utility code:
// Got this from http://www.codeproject.com/Articles/36841/Compact-Framework-Process-class-that-supports-full
private void btnKillRogue_Click(object sender, EventArgs e)
{
ProcessInfo[] list = ProcessCE.GetProcesses();
foreach (ProcessInfo item in list)
{
MessageBox.Show("Process item: " + item.FullPath);
if (item.FullPath == #"\Windows\iexplore.exe") item.Kill(); //<= this was the example search; it probably could be a problem, so I'll use it, too
if (item.FullPath.EndsWith("HHS.exe"))
{
MessageBox.Show("about to kill hhs.exe");
item.Kill();
}
if (item.FullPath.EndsWith("HUtilCE.dll"))
{
MessageBox.Show("about to kill hutilce.dll");
item.Kill();
}
}
}
Maybe there was an instance of iexplore.exe resident in memory that was problematic (I'm not showing a messagebox if that is what is found)...?

As an attempt to claim unused bounty ... do not, however, feel obligated to pass around free points on my behalf ...
Aside from force killing of possible tasks, had you rebooted the system amidst your search for an answer? If your tool did not return the message, it is certainly possible that a reboot would have done the very thing that you had attempted with the kill utility - or possible iexplore.exe had something to do with it ... the lack of the additional messagebox may leave you never knowing - unless this issue occurs again.
If no rebooting occurred, then perhaps whatever program/dll was held in memory by some other process concluded its task and released it hold.
There are several scenarios that might have occurred, it is certainly hard to determine with absolution; hence the lack of answers. I would be interested, though, if this problem occurred again.

SqlBulkCopy.WriteToServer() keep getting "connection is closed"

This makes no sense to me but maybe someone with keener eyes can spot the problem.
I have a Windows service that uses FileSystemWatcher. It processes some files and uploads data to an MSSQL database. It works totally fine on my machine -- detached from Visual Studio (ie not debugging) and running as a service. If copy this compiled code to our server, and have it point to the same database, and even the same files (!), I get this error every single time:
System.InvalidOperationException: Invalid operation. The connection is closed.
at System.Data.SqlClient.SqlConnection.GetOpenTdsConnection()
at System.Data.SqlClient.SqlBulkCopy.CopyBatchesAsyncContinuedOnError(Boolean cleanupParser)
at System.Data.SqlClient.SqlBulkCopy.<>c__DisplayClass30.<CopyBatchesAsyncContinuedOnSuccess>b__2c()
at System.Data.SqlClient.AsyncHelper.<>c__DisplayClass9.<ContinueTask>b__8(Task tsk)
I have tried pointing my local code to the server's files and it works fine. .Net 4.5.1 is on both machines. Services are both running under the same domain user. It is baffling. Perhaps there is something I don't understand about SqlBulkCopy.WriteToServerAsync()? Does it automatically share connections or something? Does it close in between calls or something? Here's the relevant code:
private static void ProcessFile(FileInfo fileInfo)
{
using (var bulkCopy = new SqlBulkCopy("Data Source=myserver;Initial Catalog=mydb;Persist Security Info=True;User ID=myusr;Password=mypwd;")
using (var objRdr = ObjectReader.Create(ReadLogFile(fileInfo)
.Where(x => !string.IsNullOrEmpty(x.Level)),
"Id", "AppId", "AppDomain", "AppMachine",
"LocalDate", "UtcDate", "Thread", "Level", "Logger", "Usrname",
"ClassName", "MethodName", "LineNo", "Message", "Exception",
"StackTrace", "Properties"))
{
bulkCopy.DestinationTableName = "EventLog";
bulkCopy.BulkCopyTimeout = 600;
bulkCopy.EnableStreaming = true;
bulkCopy.BatchSize = AppConfig.WriteBatchSize;
bulkCopy.WriteToServerAsync(objRdr).ContinueWith(t =>
{
if (t.Status == TaskStatus.Faulted)
{
CopyToFailedDirectory(fileInfo);
_log.Error(
string.Format(
"Error copying logs to database for file {0}. File has been copied to failed directory for inspection.",
fileInfo.FullName), t.Exception.InnerException ?? t.Exception);
Debug.WriteLine("new handle error {0}",
(t.Exception.InnerException ?? t.Exception).Message);
}
if (t.Status == TaskStatus.RanToCompletion)
{
_log.InfoFormat("File {0} logs have been copied to database.", fileInfo.FullName);
Debug.WriteLine("Yay, finished {0}!", fileInfo.Name);
}
// if this is the last one, delete the original file
if (t.Status == TaskStatus.Faulted || t.Status == TaskStatus.RanToCompletion)
{
Debug.WriteLine("deleting file {0}", fileInfo.Name);
PurgeFile(fileInfo);
}
});
}
}
Couple notes in case you ask:
ObjectReader is a FastMember IDataReader implementation. CRAZY fast. It reads the file into custom objects with the properties you see listed.
It throws the error for every single file.
Again, this works on my machine, both as a service and as a console app. I even had it working once on the server. It threw the error and never worked again.
Any ideas?

Looks like an issue with it being Async.
Please let me know if I wrong, but what I noticed is you have your SqlBulkCopy and ObjectReader in a using statement which is great, however, you are doing all the processing asynchronously. Once, you call it and it starts doing work, your using statements are disposing of your objects which will also kill your connection.
The odd thing is that it sounds like it works sometimes, but perhaps it just becomes a race condition at that point.

Way late to throw this one on here but I was having what I thought was the same issue with SqlBulkCopy. Tried some of the steps in the other answers but with no luck. Turns out in my case that the actual error was caused by a string in the data going above the max length on one of the varchar columns, but for some reason the only error I was getting was the one about the closed connection.
Strangely, my coworker tried the same thing, and got an actual error message about the varchar being out of bounds. So we fixed the data and everything worked, but if you're here because of this error and nothing else works, you might want to start looking for different issues in your data.

This looks to me to be a bug in the SqlBulkCopy implementation. If you run a (large) number of bulk copies in parallel in separate tasks concurrently, disable your network connection and then trigger a full garbage collection, you will reliably get this exception thrown on the GC's finalizer thread. It is completely unavoidable.
That shouldn't happen because you are continuing the WriteToServerAsync task and handling the fault. But in the implementation, on error they start a new task that they don't continue or await.
This still seems to be a bug in .NET 4.6.2.
The only fix I can see is to subscribe to TaskScheduler.UnobservedTaskException and look for something in the stacktrace that identifies the issue. That isn't a fix by the way, it is a hack.

foreach mysteriously hangs on first item of a ResourceSet

Occasionally our site slows down and the RAM usage goes up massively high. Then the app pool stops and I have to restart it. Then it's ok for a few days before the RAM suddenly spikes again and the app pool soon stops. The CPU isn't high.
Before the app pool stops I've noticed that one of our pages always hangs. The line it hangs on is a foreach on a ResourceSet :
var englishLocations = Lang.Countries.ResourceManager.GetResourceSet(new CultureInfo("en-GB"),true,true);
foreach(DictionaryEntry entry2 in englishLocations) // THIS LINE HANGS
We have the same code deployed on a different box and this doesn't happen. The main differences between the two boxes are :
Bad box
Window Server 2008 R2 Standard SP 1
IIS 7.5.7600.16385
.NET 4.5
24GB RAM
Good box
Window Server 2008 Server SP 2
IIS 7.0.6000.16386 SP 2
.NET 4.0
24GB RAM
I've tried adding uploadReadAheadSize="0" to the web.config as described here :
http://rionscode.wordpress.com/2013/03/11/resolving-controller-blocking-within-net-4-5-and-asp-net-mvc/
Which didn't work.
Why would foreach hang? It's hanging on the very first item, actually on the foreach.
Thanks.

I know it is an old post, but nevertheless... There is the potential of a deadlock when iterating over a ResourceSet and at the same time retrieving some other object through from the same Resources.
The problem is that when using a ResourceSet the iterator takes out locks on the internal resource cache of the ResourceReader http://referencesource.microsoft.com/#mscorlib/system/resources/resourcereader.cs,1389 and then in the method AllocateStringNameForIndex takes out a lock on the reader itself: http://referencesource.microsoft.com/#mscorlib/system/resources/resourcereader.cs,447
lock (_reader._resCache) {
key = _reader.AllocateStringForNameIndex(_currentName, out _dataPosition); // locks the reader
Getting an object takes out the same locks int the opposite order:
http://referencesource.microsoft.com/#mscorlib/system/resources/runtimeresourceset.cs,300
and http://referencesource.microsoft.com/#mscorlib/system/resources/runtimeresourceset.cs,335
lock(Reader) {
....
lock(_resCache) {
_resCache[key] = resLocation;
}
}
This can lead to a deadlock. We had this exact issue recently..

I experienced very similar problem.
Every once in a while IIS would hang, and I would see number of requests just sitting there. They were all in state ExecuteRequestHandler and with ManagedPipelineHandler module name.
After investigating with process explorer, I could see that all of them were sitting at mscorlib.dll!ResourceEnumerator.get_Entry, additional stack trace suggested some NGen action and then ntdll.dll!WaitForMultipleObjects.
My working hypothesis is that when multiple threads start enumerating those resources, we can run into a deadlock (possibly on some native code file generation), and alll subsequent threads then just keep on piling up.
To resolve it, I just created a critical section around this code block, to ensure that it is executed sequentially - I haven't experienced the issue since.
private static readonly object ResourceLock = new object();
public static MvcHtmlString SerializeGlobalResources(this HtmlHelper helper)
{
lock (ResourceLock)
{
// Existing code goes here ....
}
}

Based upon another answer to give you some idea how about using a try catch model ?
Perhaps it hangs because that resource isnt available / locked /..permissions etc.
var englishLocations = Lang.Countries.ResourceManager.GetResourceSet(new CultureInfo("en-GB"),true,true);
foreach(DictionaryEntry entry2 in englishLocations) // THIS LINE HANGS
ResourceManager CultureResourceManager = new ResourceManager("My.Language.Assembly", System.Reflection.Assembly.GetExecutingAssembly());
ResourceSet resourceSet = CultureResourceManager.GetResourceSet("sv-SE", true, true);
try { resourceSet.GetString("my_language_resource");}
catch (exception ex) { // from here log your error ex to wherever you like with some code }

AccessViolationException when hosting FireBirdSql in a WCF Service

I'm hosting the WCF service as a managed Windows service, and I keep getting an AccessViolationException when the consumer/client invokes its method for a second, third or fourth time. The crashes are completely random, so sometimes it might not crash until several more invocations later.
Here's the code with syntax highlighting for easier reading: http://pastebin.com/Z3Z06944
See the comments around the private method "CheckUser", since that's where the exception might be occurring.

I had a look at the code you posted, and I don't see what this has got to do with WCF. You say that commenting out the code for invoking the FireBirdSql (FbCommand?) and the AV goes away. Clearly the problem is with FireBirdSql. Try updating to the latest version, or send the crash report to the developers. An AV (access violation) typically occurs with a problem in the p/invoke unmanaged code interop layer. It sounds like some kind of multithreading problem which would be brought out in a WCF scenario.
(update: edited OP question title to include FbSQL reference)

In your code you are not explicitly closing the connection.
Since you are using the using statement it will get closed but there may be a delay.
If there is a max number of connections and the requests are coming quickly, you could get an exception if the max number is reached.
This would explain the random nature of the errors.
Edit
Your code is vulnerable to an sql server injection attack, you should fix that.
Your problem could be a locking error, do you have an index on user and password, if not you are doing a table scan, which locks the table.

I'm thinking that there are better Role / Membership provider systems in place but based on your code, you could improve this with TRY/FINALLY contructs, with the using statement.
public Boolean AddUser(string user, string pass)
{
using (FbConnection con = new FbConnection(ConfigurationManager.ConnectionStrings["DBi"].ConnectionString.ToString()))
{
using (FbCommand fbComm = new FbCommand("INSERT INTO users (name, pass) VALUES ('" + user + "','" + pass + "')", con))
{
fbComm.Connection.Open();
if (CheckUser(user, pass, con) == 0)
{
fbComm.ExecuteNonQuery();
return true;
}
fbComm.Connection.Close();
}
}
return false;
}
Have a great day!