merge revision(s) 66111: [Backport #14561]

	Avoid GCing dead stack after switching away from a fiber

	Fixes <https://bugs.ruby-lang.org/issues/14561> and discussed
	<https://bugs.ruby-lang.org/issues/15362>.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_5@66777 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/cont.c b/cont.c
index f0b8a8a0a8..558d35c4bd 100644
--- a/cont.c
+++ b/cont.c
@@ -1616,6 +1616,7 @@ fiber_store(rb_fiber_t *next_fib, rb_thread_t *th)
     return fib->cont.value;
 
 #else /* FIBER_USE_NATIVE */
+    fib->cont.saved_ec.machine.stack_end = NULL;
     if (ruby_setjmp(fib->cont.jmpbuf)) {
 	/* restored */
 	fib = th->ec->fiber_ptr;