Fix #3578: return a dummy result when an STM transaction is aborted

[ghc-hetmet.git] / rts / RaiseAsync.c

diff --git a/rts/RaiseAsync.c b/rts/RaiseAsync.c
index 4ca1cba..6510ce8 100644 (file)
--- a/rts/RaiseAsync.c
+++ b/rts/RaiseAsync.c
@@ -18,7 +18,6 @@
 #include "STM.h"
 #include "Sanity.h"
 #include "Profiling.h"
-#include "eventlog/EventLog.h"
 #if defined(mingw32_HOST_OS)
 #include "win32/IOManager.h"
 #endif
@@ -162,11 +161,7 @@ throwTo (Capability *cap,  // the Capability we hold
               (unsigned long)source->id, (unsigned long)target->id);
 
 #ifdef DEBUG
-    if (traceClass(DEBUG_sched)) {
-       debugTraceBegin("throwTo: target");
-       printThreadStatus(target);
-       debugTraceEnd();
-    }
+    traceThreadStatus(DEBUG_sched, target);
 #endif
 
     goto check_target;
@@ -891,7 +886,17 @@ raiseAsync(Capability *cap, StgTSO *tso, StgClosure *exception,
            if (stop_at_atomically) {
                ASSERT(stmGetEnclosingTRec(tso->trec) == NO_TREC);
                stmCondemnTransaction(cap, tso -> trec);
-               tso->sp = frame;
+               tso->sp = frame - 2;
+                // The ATOMICALLY_FRAME expects to be returned a
+                // result from the transaction, which it stores in the
+                // stack frame.  Hence we arrange to return a dummy
+                // result, so that the GC doesn't get upset (#3578).
+                // Perhaps a better way would be to have a different
+                // ATOMICALLY_FRAME instance for condemned
+                // transactions, but I don't fully understand the
+                // interaction with STM invariants.
+                tso->sp[1] = (W_)&stg_NO_TREC_closure;
+                tso->sp[0] = (W_)&stg_gc_unpt_r1_info;
                tso->what_next = ThreadRunGHC;
                return;
            }