merge revision(s) 54256: [Backport #12118] [Backport #12218]

	* thread_pthread.c (reserve_stack): fix reserving position where
	  the stack growing bottom to top. [Bug #12118]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_1@54394 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 28 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 64a390e9b9..9d124da903 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue Mar 29 21:07:30 2016  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* thread_pthread.c (reserve_stack): fix reserving position where
+	  the stack growing bottom to top. [Bug #12118]
+
 Fri Mar 25 18:42:46 2016  Koichi ITO  <koic.ito@gmail.com>
 
 	* variable.c: Added documentation about order of `Module#constants`
diff --git a/thread_pthread.c b/thread_pthread.c
index 47e94156e1..31098ed4ed 100644
--- a/thread_pthread.c
+++ b/thread_pthread.c
@@ -675,17 +675,31 @@ reserve_stack(volatile char *limit, size_t size)
 	const volatile char *end = buf + sizeof(buf);
 	limit += size;
 	if (limit > end) {
-	    size = limit - end;
-	    limit = alloca(size);
-	    limit[stack_check_margin+size-1] = 0;
+	    /* |<-bottom (=limit(a))                                     top->|
+	     * | .. |<-buf 256B |<-end                          | stack check |
+	     * |  256B  |              =size=                   | margin (4KB)|
+	     * |              =size=         limit(b)->|  256B  |             |
+	     * |                |       alloca(sz)     |        |             |
+	     * | .. |<-buf      |<-limit(c)    [sz-1]->0>       |             |
+	     */
+	    size_t sz = limit - end;
+	    limit = alloca(sz);
+	    limit[sz-1] = 0;
 	}
     }
     else {
 	limit -= size;
 	if (buf > limit) {
-	    limit = alloca(buf - limit);
-	    limit[0] = 0; /* ensure alloca is called */
-	    limit -= stack_check_margin;
+	    /* |<-top (=limit(a))                                     bottom->|
+	     * | .. | 256B buf->|                               | stack check |
+	     * |  256B  |              =size=                   | margin (4KB)|
+	     * |              =size=         limit(b)->|  256B  |             |
+	     * |                |       alloca(sz)     |        |             |
+	     * | .. |      buf->|           limit(c)-><0>       |             |
+	     */
+	    size_t sz = buf - limit;
+	    limit = alloca(sz);
+	    limit[0] = 0;
 	}
     }
 }
diff --git a/version.h b/version.h
index 6780a2ae89..d4acd19748 100644
--- a/version.h
+++ b/version.h
@@ -1,10 +1,10 @@
 #define RUBY_VERSION "2.1.9"
-#define RUBY_RELEASE_DATE "2016-03-26"
-#define RUBY_PATCHLEVEL 486
+#define RUBY_RELEASE_DATE "2016-03-29"
+#define RUBY_PATCHLEVEL 487
 
 #define RUBY_RELEASE_YEAR 2016
 #define RUBY_RELEASE_MONTH 3
-#define RUBY_RELEASE_DAY 26
+#define RUBY_RELEASE_DAY 29
 
 #include "ruby/version.h"