diff options
Diffstat (limited to 'win/tclWinConsole.c')
-rw-r--r-- | win/tclWinConsole.c | 53 |
1 files changed, 51 insertions, 2 deletions
diff --git a/win/tclWinConsole.c b/win/tclWinConsole.c index ab55035..5c0b43b 100644 --- a/win/tclWinConsole.c +++ b/win/tclWinConsole.c @@ -51,6 +51,8 @@ TCL_DECLARE_MUTEX(consoleMutex) typedef struct ConsoleThreadInfo { HANDLE thread; /* Handle to reader or writer thread. */ + HANDLE threadInitialized; /* Manual-reset event to signal that thread has been initialized. */ + int threadExiting; /* Boolean indicating that thread is exiting. */ HANDLE readyEvent; /* Manual-reset event to signal _to_ the main * thread when the worker thread has finished * waiting for its normal work to happen. */ @@ -536,9 +538,12 @@ StartChannelThread( threadInfoPtr->readyEvent = CreateEvent(NULL, TRUE, TRUE, NULL); threadInfoPtr->startEvent = CreateEvent(NULL, FALSE, FALSE, NULL); + threadInfoPtr->threadInitialized = CreateEvent(NULL, TRUE, FALSE, NULL); + threadInfoPtr->threadExiting = FALSE; threadInfoPtr->stopEvent = CreateEvent(NULL, FALSE, FALSE, NULL); threadInfoPtr->thread = CreateThread(NULL, 256, threadProc, infoPtr, 0, &id); + WaitForSingleObject(threadInfoPtr->threadInitialized, INFINITE); /* wait for thread to initialize */ SetThreadPriority(threadInfoPtr->thread, THREAD_PRIORITY_HIGHEST); } @@ -572,11 +577,28 @@ StopChannelThread( * Note that we need to guard against terminating the thread while * it is in the middle of Tcl_ThreadAlert because it won't be able * to release the notifier lock. + * + * Also note that terminating threads during their initialization or teardown phase + * may result in ntdll.dll's LoaderLock to remain locked indefinitely. + * This causes ntdll.dll's LdrpInitializeThread() to deadlock trying to acquire LoaderLock. + * LdrpInitializeThread() is executed within new threads to perform + * initialization and to execute DllMain() of all loaded dlls. + * As a result, all new threads are deadlocked in their initialization phase and never execute, + * even though CreateThread() reports successful thread creation. + * This results in a very weird process-wide behavior, which is extremely hard to debug. + * + * THREADS SHOULD NEVER BE TERMINATED. Period. + * + * But for now, check if thread is exiting, and if so, let it die peacefully. */ Tcl_MutexLock(&consoleMutex); - /* BUG: this leaks memory. */ - TerminateThread(threadInfoPtr->thread, 0); + if ( threadInfoPtr->threadExiting ) { + WaitForSingleObject(threadInfoPtr->thread, INFINITE); + } else { + /* BUG: this leaks memory. */ + TerminateThread(threadInfoPtr->thread, 0); + } Tcl_MutexUnlock(&consoleMutex); } } @@ -587,6 +609,7 @@ StopChannelThread( */ CloseHandle(threadInfoPtr->thread); + CloseHandle(threadInfoPtr->threadInitialized); CloseHandle(threadInfoPtr->readyEvent); CloseHandle(threadInfoPtr->startEvent); CloseHandle(threadInfoPtr->stopEvent); @@ -1186,6 +1209,11 @@ ConsoleReaderThread( HANDLE wEvents[2]; /* + * Notify StartChannelThread() that this thread is initialized + */ + SetEvent(threadInfo->threadInitialized); + + /* * The first event takes precedence. */ @@ -1253,6 +1281,14 @@ ConsoleReaderThread( Tcl_MutexUnlock(&consoleMutex); } + /* + * Inform StopChannelThread() that this thread should not be terminated, since it is about to exit. + * See comment in StopChannelThread() for reasons. + */ + Tcl_MutexLock(&consoleMutex); + threadInfo->threadExiting = TRUE; + Tcl_MutexUnlock(&consoleMutex); + return 0; } @@ -1287,6 +1323,11 @@ ConsoleWriterThread( HANDLE wEvents[2]; /* + * Notify StartChannelThread() that this thread is initialized + */ + SetEvent(threadInfo->threadInitialized); + + /* * The first event takes precedence. */ @@ -1351,6 +1392,14 @@ ConsoleWriterThread( Tcl_MutexUnlock(&consoleMutex); } + /* + * Inform StopChannelThread() that this thread should not be terminated, since it is about to exit. + * See comment in StopChannelThread() for reasons. + */ + Tcl_MutexLock(&consoleMutex); + threadInfo->threadExiting = TRUE; + Tcl_MutexUnlock(&consoleMutex); + return 0; } |