merge revision(s) 2e7e153a2af1456515d43b6381e38534b069b1c2: [Backport #19242]

	[Bug #19242] Prohibit circular causes to be loaded

	---
	 error.c                     |  4 ++++
	 eval.c                      |  4 ++++
	 eval_error.c                | 11 +++++++++++
	 test/ruby/test_exception.rb | 12 ++++++++++++
	 4 files changed, 31 insertions(+)

1 files changed, 4 insertions, 0 deletions

diff --git a/error.c b/error.c
index a870d0200b..65ad20a27b 100644
--- a/error.c
+++ b/error.c
@@ -2846,6 +2846,8 @@ ivar_copy_i(st_data_t key, st_data_t val, st_data_t exc)
     return ST_CONTINUE;
 }
 
+void rb_exc_check_circular_cause(VALUE exc);
+
 static VALUE
 exception_loader(VALUE exc, VALUE obj)
 {
@@ -2860,6 +2862,8 @@ exception_loader(VALUE exc, VALUE obj)
 
     rb_ivar_foreach(obj, ivar_copy_i, exc);
 
+    rb_exc_check_circular_cause(exc);
+
     if (rb_attr_get(exc, id_bt) == rb_attr_get(exc, id_bt_locations)) {
         rb_ivar_set(exc, id_bt_locations, Qnil);
     }