second attempt to fix [perl #24914] freeing a CV reference that was

currently being executed caused coredumps. The dounwind called by
die unwinds all the contexts on the context stack before unwinding
the save stack.  To stop premature freeing of the CV, hold
references to it on both stacks.

p4raw-id: //depot/perl@22182

1 files changed, 11 insertions, 2 deletions

diff --git a/cop.h b/cop.h
index 2e30eafb66..3d1191c9bb 100644
--- a/cop.h
+++ b/cop.h
@@ -121,11 +121,20 @@ struct block_sub {
     PAD		*oldcomppad;
 };
 
-/* base for the next two macros. Don't use directly */
+/* base for the next two macros. Don't use directly.
+ * Note that the refcnt of the cv is incremented twice;  The CX one is
+ * decremented by LEAVESUB, the other by LEAVE. */
+
 #define PUSHSUB_BASE(cx)						\
 	cx->blk_sub.cv = cv;						\
 	cx->blk_sub.olddepth = CvDEPTH(cv);				\
-	cx->blk_sub.hasargs = hasargs;
+	cx->blk_sub.hasargs = hasargs;					\
+	if (!CvDEPTH(cv)) {						\
+	    (void)SvREFCNT_inc(cv);					\
+	    (void)SvREFCNT_inc(cv);					\
+	    SAVEFREESV(cv);						\
+	}
+
 
 #define PUSHSUB(cx)							\
 	PUSHSUB_BASE(cx)						\