From 0c0f75b7983e6083ad21690149bf79ea878c6804 Mon Sep 17 00:00:00 2001
From: naruse <naruse@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 17 May 2017 07:13:47 +0000
Subject: [PATCH] Treat NULL reference case [Bug #13566]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58769 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 vm_dump.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/vm_dump.c b/vm_dump.c
index d423f1a5a4..f249b7efec 100644
--- a/vm_dump.c
+++ b/vm_dump.c
@@ -475,8 +475,8 @@ darwin_sigtramp:
 	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 = uctx->uc_mcontext->__ss.__rip;
-	if (((char*)ip)[-2] == 0x0f && ((char*)ip)[-1] == 5) {
-	    /* signal received in syscall */
+	if (!ip || (((char*)ip)[-2] == 0x0f && ((char*)ip)[-1] == 5)) {
+	    /* NULL reference or signal received in syscall */
 	    trace[n++] = (void *)ip;
 	    ip = *(unw_word_t*)uctx->uc_mcontext->__ss.__rsp;
 	}