Prevent the stack from being marked twice

This commit prevents the stack from being marked twice: once via the
Fiber, and once via the Thread.  It introduces an assertion to assert
that the ec on the thread is the same as the ec on the Fiber being
marked via the thread.

1 files changed, 6 insertions, 0 deletions

diff --git a/cont.c b/cont.c
index 36f47d9ee6..590d6c250f 100644
--- a/cont.c
+++ b/cont.c
@@ -1194,6 +1194,12 @@ cont_init_mjit_cont(rb_context_t *cont)
     }
 }
 
+struct rb_execution_context_struct *
+rb_fiberptr_get_ec(struct rb_fiber_struct *fiber)
+{
+    return &fiber->cont.saved_ec;
+}
+
 static void
 cont_init(rb_context_t *cont, rb_thread_t *th)
 {