We shouldn't try to decrement the refcount of PL_warnhook

if it has been set to PERL_WARNHOOK_FATAL.

p4raw-id: //depot/perl@28669

1 files changed, 2 insertions, 1 deletions

diff --git a/mg.c b/mg.c
index 8e00fb20ae..3f2fd5a489 100644
--- a/mg.c
+++ b/mg.c
@@ -1384,7 +1384,8 @@ Perl_magic_setsig(pTHX_ SV *sv, MAGIC *mg)
 	    Perl_croak(aTHX_ "No such hook: %s", s);
 	i = 0;
 	if (*svp) {
-	    to_dec = *svp;
+	    if (*svp != PERL_WARNHOOK_FATAL)
+		to_dec = *svp;
 	    *svp = NULL;
 	}
     }