How to get non-current thread's stacktrace?

Here's what's worked for me so far:

StackTrace GetStackTrace (Thread targetThread)
{
    StackTrace stackTrace = null;
    var ready = new ManualResetEventSlim();

    new Thread (() =>
    {
        // Backstop to release thread in case of deadlock:
        ready.Set();
        Thread.Sleep (200);
        try { targetThread.Resume(); } catch { }
    }).Start();

    ready.Wait();
    targetThread.Suspend();
    try { stackTrace = new StackTrace (targetThread, true); }
    catch { /* Deadlock */ }
    finally
    {
        try { targetThread.Resume(); }
        catch { stackTrace = null;  /* Deadlock */  }
    }

    return stackTrace;
}

If it deadlocks, the deadlock is automatically freed and you get back a null trace. (You can then call it again.)

I should add that after a few days of testing, I've only once been able to create a deadlock on my Core i7 machine. Deadlocks are common, though, on single-core VM when the CPU runs at 100%.

This is an old Thread, but just wanted to warn about the proposed solution: The Suspend and Resume solution does not work - I just experienced a deadlock in my code trying the sequence Suspend/StackTrace/Resume.

The Problem is that StackTrace constructor does RuntimeMethodHandle -> MethodBase conversions, and this changes a internal MethodInfoCache, which takes a lock. The deadlock occurred because the thread I was examining also was doing reflection, and was holding that lock.

It is a pity that the suspend/resume stuff is not done inside the StackTrace constructor -then this problem could easily have been circumvented.

According to C# 3.0 in a Nutshell, this is one of the few situations where it is okay to call Suspend/Resume.