From 622da08564f02443b40426a19c25f82e89071cac Mon Sep 17 00:00:00 2001
From: simonmar <unknown>
Date: Mon, 15 Dec 2003 14:31:48 +0000
Subject: [PATCH] [project @ 2003-12-15 14:31:48 by simonmar] Fix locking bug
 in awaitEvent(): in one code path it could return with
 sched_lock unlocked.

---
 ghc/rts/win32/AwaitEvent.c |   16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/ghc/rts/win32/AwaitEvent.c b/ghc/rts/win32/AwaitEvent.c
index a8f73ff..0df8023 100644
--- a/ghc/rts/win32/AwaitEvent.c
+++ b/ghc/rts/win32/AwaitEvent.c
@@ -23,13 +23,18 @@
 void
 awaitEvent(rtsBool wait)
 {
-  RELEASE_LOCK(&sched_mutex);
+  int ret;
+
   do {
-    /* Try to de-queue completed IO requests */
-    if (!awaitRequests(wait)) {
-      return;
-    }
+    /* Try to de-queue completed IO requests
+     */
+    RELEASE_LOCK(&sched_mutex);
+    ret = awaitRequests(wait);
     ACQUIRE_LOCK(&sched_mutex);
+    if (!ret) { 
+      return; /* still hold the lock */
+    }
+
     /* we were interrupted, return to the scheduler immediately.
      */
     if (interrupted) {
@@ -51,7 +56,6 @@ awaitEvent(rtsBool wait)
       return; /* still hold the lock */
     }
 #endif
-    RELEASE_LOCK(&sched_mutex);
   } while (wait && !interrupted && run_queue_hd == END_TSO_QUEUE);
 }
 
-- 
1.7.10.4