# http://rt.perl.org/rt3/Public/Bug/Display.html?id=52074
# http://rt.perl.org/rt3/Public/Bug/Display.html?id=54566
# http://perl5.git.perl.org/perl.git/commitdiff/5562fa714b8071354c365365c26a950efa73179a?hp=b3562f19ee0d76b60d176a0b1cfdac4f5f36785c
# http://perl5.git.perl.org/perl.git/commitdiff/ea86b3de3510ce31d0c08dd6a21701d74b25369d?hp=72bfe1b2b35945ea3c95d9b94ae2908121292236
diff --git a/mg.c b/mg.c
index c4d7aeb..91a36f2 100644
--- mg.c
+++ mg.c
@@ -1543,10 +1543,11 @@ Perl_magic_setisa(pTHX_ SV *sv, MAGIC *mg)
     stash = GvSTASH(
         SvTYPE(mg->mg_obj) == SVt_PVGV
             ? (GV*)mg->mg_obj
-            : (GV*)SvMAGIC(mg->mg_obj)->mg_obj
+            : (GV*)mg_find(mg->mg_obj, PERL_MAGIC_isa)->mg_obj
     );
 
-    mro_isa_changed_in(stash);
+    if (stash)
+	mro_isa_changed_in(stash);
 
     return 0;
 }
diff --git a/t/mro/pkg_gen.t b/t/mro/pkg_gen.t
index 6a507ac..e1f5eb0 100644
--- t/mro/pkg_gen.t
+++ t/mro/pkg_gen.t
@@ -4,7 +4,7 @@ use strict;
 use warnings;
 
 chdir 't' if -d 't';
-require q(./test.pl); plan(tests => 6);
+require q(./test.pl); plan(tests => 7);
 
 {
     package Foo;
@@ -34,3 +34,7 @@ is(mro::get_pkg_gen('Foo'), 1, "pkg_gen 1 for undef %Pkg::");
 
 delete $::{"Foo::"};
 is(mro::get_pkg_gen('Foo'), 0, 'pkg_gen 0 for delete $::{Pkg::}');
+
+delete $::{"Quux::"};
+push @Quux::ISA, "Woot"; # should not segfault
+ok(1, "No segfault on modification of ISA in a deleted stash");