CODEWITHSUNDEEP
c#exceptionprocess
Kyle Uithoven
Kyle Uithoven

Reputation: 2444

C# Only part of a ReadProcessMemory or WriteProcessMemory request was completed during Process.Kill()

I have been researching this issue pretty extensively and cannot seem to find an answer.

I know that the Only part of a ReadProcessMemory or WriteProcessMemory request was completed exception is thrown when a 32-bit process tries to access a 64-bit process and the same for a 64-bit modifying a 32-bit process.

The solution to that issue is to change the Platform Target to 'Any CPU'. I have tried this and unfortunately this does not solve my issue.

The next block of code is what keeps throwing the exception. The program that runs this code is used to open up applications on remote computers and keeps a list of all the processes that the program itself opened so that I don't have to loop through all the processes. 

Process processToRemove = null;
lock (_runningProcesses)
{
    foreach (Process p in _runningProcesses)
    {
        foreach (ProcessModule module in p.Modules)
        {
            string[] strs = text.Split('\\');

            if (module.ModuleName.Equals(strs[strs.Length - 1]))
            {
                processToRemove = p;
                break;
            }
        }
        if (processToRemove != null)
        {
            break;
        }
    }
    if (processToRemove != null)
    {
        processToRemove.Kill();
        _runningProcesses.Remove(processToRemove);
    }
}

These processes can and most likely will be 32-bit and 64-bit, mixed together.

Is there anything I am doing that I shouldn't be doing, or is there just a better way to do all of this?

Upvotes: 20

Views: 25012

Answers (3)

mlorbetske
mlorbetske

Reputation: 5649

I agree with @sprinter252 that _runningProcesses should not be used as your sync object here.

//Somewhere that is accessible to both the thread getting the process list and the thread the 
//code below will be running, declare your sync, lock while adjusting _runningProcesses
public static readonly object Sync = new object();

IList<Process> runningProcesses;
lock(Sync)
{
    runningProcesses = _runningProcesses.ToList();
}
Process processToRemove = null;
foreach (Process p in _runningProcesses)
{
    foreach (ProcessModule module in p.Modules)
    {
        string[] strs = text.Split('\\');
        if (module.ModuleName.Equals(strs[strs.Length - 1]))
        {
            processToRemove = p;
            break;
        }
    }
    if (processToRemove != null)
    {
        break;
    }
}
if (processToRemove != null)
{
    //If we've got a process that needs killing, re-lock on Sync so that we may 
    //safely modify the shared collection
    lock(Sync)
    {
        processToRemove.Kill();
        _runningProcesses.Remove(processToRemove);
    }
}

If this code is wrapped in a loop to continue to check _runningProcesses for the process you wish to kill, consider changing processToRemove to processesToRemove and change it's type to a collection, iterate over that list in the bottom block after a check for a non-zero count and lock outside of that loop to decrease the overhead of obtaining and releasing locks per process to kill.

Upvotes: 0

miniBill
miniBill

Reputation: 1734

As detailed in the comments of the MSDN page for Process.Modules and this thread there is a known issue in Process.Modules when enumerating 32 bit processes from a 64 bit process and visa-versa:

Internally .NET's Process.Modules is using function EnumProcessModules from PSAPI.dll. This function has a known issue that it cannot work across 32/64 bit process boundary. Therefore enumerating another 64-bit process from 32-bit process or vice versa doesn't work correctly.

The solution seems to be to use the EnumProcessModulesEx function, (which must be called via P/Invoke), however this function is only available on later versions of Windows.

We fixed this issue by adding a new function called EnumProcessModulesEx to PSAPI.dll (http://msdn2.microsoft.com/en-us/library/ms682633.aspx), but we currently cannot use it in this case:

  • it only works on Windows Vista or Windows Server 2008
  • currently .NET 2.0 Framework don't have a service pack or hotfix to make Process.Modules use this new API

Upvotes: 19

Alexander Schmidt
Alexander Schmidt

Reputation: 5723

There are only some issues regarding the handling of the processes and the locking that I would change:

object lockObject = new object();
List<Process> processesToRemove = new List<Process>();
foreach (Process p in _runningProcesses)
{
    foreach (ProcessModule module in p.Modules)
    {
        string[] strs = text.Split('\\');

        if (module.ModuleName.Equals(strs[strs.Length - 1]))
        {
            processesToRemove.Add(p);
            break;
        }
    }                    
}                
lock (lockObject)
{
    foreach (Process p in processesToRemove)
    {                 
        p.Kill();
        _runningProcesses.Remove(p);
    }                
}

I'm not answering for the bounty, just wanted to give some ideas. This code isn't tested because I don't exactly know what you are trying to do there.

Just consider not to lock the process-list and to keep the lock as short as possible.

Upvotes: 3

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