// Called by any thread to check the wait chain and deadlock state of another thread (or itself)
private IList <WaitChainInfo> GetWaitChainI(Int32 targetThreadId)
{
// Initialize the wait chain result
List <WaitChainInfo> waitChain = new List <WaitChainInfo>();
lock (m_syncLock) {
// Walk the wait chain
for (Int32 blockedThreadId = targetThreadId; true;)
{
// Determine if the thread in question is blocked and what it is blocked on.
ThreadBlockInfo blockedThreadInfo = GetBlockedThreadInfo(blockedThreadId);
// If the thread is not in a wait state, just return
if (blockedThreadInfo == null)
{
return(waitChain);
}
// Do we know what thread this thread is blocked on?
Int32 blockingThreadId = blockedThreadInfo.BlockingThreadId;
if (blockingThreadId == 0)
{
// We don't know, try to detect it
ThreadBlockInfo blockingThreadInfo = GetBlockingThreadInfo(
blockedThreadInfo.BlockObject, blockedThreadInfo.AcquiredExclusively);
if (blockingThreadInfo != null)
{
blockingThreadId = blockingThreadInfo.BlockedThreadId;
}
}
// Add the thread that is currently blocked to the wait chain
waitChain.Add(new WaitChainInfo(blockedThreadId, blockingThreadId, blockedThreadInfo.BlockObject));
// If no thread is blocking the blocked thread, there is no deadlock
if (blockingThreadId == 0)
{
return(waitChain);
}
// If the owning thread is the original target thread, then we have a deadlock situation
if (blockingThreadId == targetThreadId)
{
throw new Exception <DeadlockExceptionArgs>(
new DeadlockExceptionArgs(waitChain),
"Deadlock");
}
// Traverse what this thread is blocked on...
blockedThreadId = blockingThreadId;
}
}
}
private void BlockThreadAndCheckDeadlock(ThreadBlockInfo tli)
{
try {
Monitor.Enter(m_syncLock);
m_BlockedThreads.Add(tli);
Monitor.Exit(m_syncLock);
// Check for deadlock (wait chain result is thrown away)
GetWaitChainI(Thread.CurrentThread.ManagedThreadId);
}
catch {
// If anything goes wrong (most-likely a DeadlockException),
// cleanup by indicating that this thread did not block because it
// will not acquire the lock
UnblockI(false);
throw;
}
}
private void BlockThreadAndCheckDeadlock(ThreadBlockInfo tli) {
try {
Monitor.Enter(m_syncLock);
m_BlockedThreads.Add(tli);
Monitor.Exit(m_syncLock);
// Check for deadlock (wait chain result is thrown away)
GetWaitChainI(Thread.CurrentThread.ManagedThreadId);
}
catch {
// If anything goes wrong (most-likely a DeadlockException),
// cleanup by indicating that this thread did not block because it
// will not acquire the lock
UnblockI(false);
throw;
}
}
