X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=rts%2FHeapStackCheck.cmm;h=ba672bf805895b4a872120ae718d5ea97cfb927b;hb=1e31c2960f7a9fc61119237d8a35b0516d6accca;hp=a528a3f22e81edbb686d06c9d9b871223a917d6a;hpb=7408b39235bccdcde48df2a73337ff976fbc09b7;p=ghc-hetmet.git

diff --git a/rts/HeapStackCheck.cmm b/rts/HeapStackCheck.cmm
index a528a3f..ba672bf 100644
--- a/rts/HeapStackCheck.cmm
+++ b/rts/HeapStackCheck.cmm
@@ -631,8 +631,12 @@ INFO_TABLE_RET( stg_block_throwto, RET_SMALL, P_ unused, P_ unused )
 
 stg_block_throwto_finally
 {
-    // unlock the throwto message
-    unlockClosure(StgTSO_block_info(CurrentTSO), stg_MSG_THROWTO_info);
+    // unlock the throwto message, but only if it wasn't already
+    // unlocked.  It may have been unlocked if we revoked the message
+    // due to an exception being raised during threadPaused().
+    if (StgHeader_info(StgTSO_block_info(CurrentTSO)) == stg_WHITEHOLE_info) {
+        unlockClosure(StgTSO_block_info(CurrentTSO), stg_MSG_THROWTO_info);
+    }
     jump StgReturn;
 }