merge revision(s) 56030,56035: [Backport #12711]

	* vm_dump.c (backtrace): use rip in the saved context for the case
	  the SIGSEGV is received when the process is in userland.
	  Note that ip in the stack should be used if the signal is received
	  when it is in kernel (when it is calling syscall) [Bug #12711]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@56257 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,10 @@
+Mon Sep 26 23:10:43 2016  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* vm_dump.c (backtrace): use rip in the saved context for the case
+	  the SIGSEGV is received when the process is in userland.
+	  Note that ip in the stack should be used if the signal is received
+	  when it is in kernel (when it is calling syscall) [Bug #12711]
+
 Mon Sep 26 20:23:32 2016  CHIKANAGA Tomoyuki  <nagachika@ruby-lang.org>
 
 	* gems/bundled_gems: update minitest to 5.8.5.

version.h

@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.2"
 #define RUBY_RELEASE_DATE "2016-09-26"
-#define RUBY_PATCHLEVEL 189
+#define RUBY_PATCHLEVEL 190
 
 #define RUBY_RELEASE_YEAR 2016
 #define RUBY_RELEASE_MONTH 9

vm_dump.c

@@ -482,10 +482,14 @@ backtrace(void **trace, int size)
 	unw_set_reg(&cursor, UNW_X86_64_R13, uctx->uc_mcontext->__ss.__r13);
 	unw_set_reg(&cursor, UNW_X86_64_R14, uctx->uc_mcontext->__ss.__r14);
 	unw_set_reg(&cursor, UNW_X86_64_R15, uctx->uc_mcontext->__ss.__r15);
-	ip = *(unw_word_t*)uctx->uc_mcontext->__ss.__rsp;
-	unw_set_reg(&cursor, UNW_REG_IP, ip);
-	trace[n++] = (void *)uctx->uc_mcontext->__ss.__rip;
+	ip = uctx->uc_mcontext->__ss.__rip;
+	if (((char*)ip)[-2] == 0x0f && ((char*)ip)[-1] == 5) {
+	    /* signal received in syscall */
+	    trace[n++] = (void *)ip;
+	    ip = *(unw_word_t*)uctx->uc_mcontext->__ss.__rsp;
+	}
 	trace[n++] = (void *)ip;
+	unw_set_reg(&cursor, UNW_REG_IP, ip);
     }
     while (unw_step(&cursor) > 0) {
 	unw_get_reg(&cursor, UNW_REG_IP, &ip);