merge revision(s) 51626: [Backport #11457]

	* thread_pthread.c (reserve_stack): ensure the memory is really
	  allocated. [Bug #11457]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@51985 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/thread_pthread.c b/thread_pthread.c
index 5fcad19ebd..2a47efedd3 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -686,8 +686,8 @@ reserve_stack(volatile char *limit, size_t size)
 	limit -= size;
 	if (buf > limit) {
 	    limit = alloca(buf - limit);
+	    limit[0] = 0; /* ensure alloca is called */
 	    limit -= stack_check_margin;
-	    limit[0] = 0;
 	}
     }
 }