From bb7b45dcf16118fb03bf28aea08a168ac6598a33 Mon Sep 17 00:00:00 2001
From: Simon Marlow <marlowsd@gmail.com>
Date: Wed, 27 Jan 2010 13:54:30 +0000
Subject: [PATCH] Don't Terminate the ticker thread (#3748)

---
 rts/RtsStartup.c   |    2 +-
 rts/Ticker.h       |    2 +-
 rts/Timer.c        |    4 ++--
 rts/Timer.h        |    2 +-
 rts/posix/Itimer.c |    2 +-
 rts/win32/Ticker.c |   21 +++++++++++++++------
 6 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/rts/RtsStartup.c b/rts/RtsStartup.c
index f0b2598..8e2eac4 100644
--- a/rts/RtsStartup.c
+++ b/rts/RtsStartup.c
@@ -370,7 +370,7 @@ hs_exit_(rtsBool wait_foreign)
 
     /* stop the ticker */
     stopTimer();
-    exitTimer();
+    exitTimer(wait_foreign);
 
     // set the terminal settings back to what they were
 #if !defined(mingw32_HOST_OS)    
diff --git a/rts/Ticker.h b/rts/Ticker.h
index 3e62622..37c2696 100644
--- a/rts/Ticker.h
+++ b/rts/Ticker.h
@@ -16,7 +16,7 @@ typedef void (*TickProc)(int);
 void initTicker  (nat ms, TickProc handle_tick);
 void startTicker (void);
 void stopTicker  (void);
-void exitTicker  (void);
+void exitTicker  (rtsBool wait);
 
 END_RTS_PRIVATE
 
diff --git a/rts/Timer.c b/rts/Timer.c
index 8c178a0..a5d42fb 100644
--- a/rts/Timer.c
+++ b/rts/Timer.c
@@ -114,9 +114,9 @@ stopTimer(void)
 }
 
 void
-exitTimer(void)
+exitTimer (rtsBool wait)
 {
     if (RtsFlags.MiscFlags.tickInterval != 0) {
-        exitTicker();
+        exitTicker(wait);
     }
 }
diff --git a/rts/Timer.h b/rts/Timer.h
index f0b5459..b03ef06 100644
--- a/rts/Timer.h
+++ b/rts/Timer.h
@@ -10,6 +10,6 @@
 #define TIMER_H
 
 RTS_PRIVATE void initTimer (void);
-RTS_PRIVATE void exitTimer (void);
+RTS_PRIVATE void exitTimer (rtsBool wait);
 
 #endif /* TIMER_H */
diff --git a/rts/posix/Itimer.c b/rts/posix/Itimer.c
index 3a09e80..2dbf32d 100644
--- a/rts/posix/Itimer.c
+++ b/rts/posix/Itimer.c
@@ -221,7 +221,7 @@ stopTicker(void)
 }
 
 void
-exitTicker(void)
+exitTicker (rtsBool wait STG_UNUSED)
 {
 #if defined(USE_TIMER_CREATE)
     timer_delete(timer);
diff --git a/rts/win32/Ticker.c b/rts/win32/Ticker.c
index 6be1b3a..929e6f4 100644
--- a/rts/win32/Ticker.c
+++ b/rts/win32/Ticker.c
@@ -127,7 +127,7 @@ stopTicker(void)
 }
 
 void
-exitTicker(void)
+exitTicker (rtsBool wait)
 {
     // We must wait for the ticker thread to terminate, since if we
     // are in a DLL that is about to be unloaded, the ticker thread
@@ -138,10 +138,20 @@ exitTicker(void)
 	DWORD exitCode;
         ticker_state = TickerExit;
 	SetEvent(hStopEvent);
-	while (1) {
-	    WaitForSingleObject(tickThread, 20);
+	while (wait) {
+            // See #3748:
+            //
+            // when the RTS is compiled into a DLL (wait==rtsTrue),
+            // the ticker thread must stop before we exit, or chaos
+            // will ensue.  We can't kill it, because it may be
+            // holding a lock.
+            //
+            // When not compiled into a DLL, we wait for
+            // the thread out of courtesy, but give up after 200ms if
+            // it still hasn't stopped.
+	    WaitForSingleObject(tickThread, 200);
 	    if (!GetExitCodeThread(tickThread, &exitCode)) {
-		return 1;
+		return;
 	    }
 	    if (exitCode != STILL_ACTIVE) {
 		tickThread = INVALID_HANDLE_VALUE;
@@ -149,9 +159,8 @@ exitTicker(void)
 		    CloseHandle(hStopEvent);
 		    hStopEvent = INVALID_HANDLE_VALUE;
 		}
-		return 0;
+		return;
 	    }
-	    TerminateThread(tickThread, 0);
 	}
     }
 }
-- 
1.7.10.4