From df2a97c99c651bfde9daf496e0ba02aa829dc098 Mon Sep 17 00:00:00 2001
From: Kris Van Hees <kris.van.hees@oracle.com>
Date: Thu, 17 Oct 2013 05:45:22 -0400
Subject: [PATCH] dtrace: ensure userspace stack memory access cannot page
 fault

Orabug: 17591351

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>
---
 dtrace/dtrace_isa.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/dtrace/dtrace_isa.c b/dtrace/dtrace_isa.c
index 428db59a2d94..605ec9df2d05 100644
--- a/dtrace/dtrace_isa.c
+++ b/dtrace/dtrace_isa.c
@@ -29,6 +29,7 @@
 #include <linux/hardirq.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
+#include <linux/uaccess.h>
 #include <asm/stacktrace.h>
 
 #include "dtrace.h"
@@ -297,7 +298,14 @@ void dtrace_getufpstack(uint64_t *pcstack, uint64_t *fpstack,
 
 	for (sp = (unsigned long *)tos;
 	     sp <= (unsigned long *)bos && pcstack_limit; sp++) {
-		unsigned long	addr = *sp;
+		unsigned long	addr;
+
+		DTRACE_CPUFLAG_SET(CPU_DTRACE_NOFAULT);
+		get_user(addr, sp);
+		DTRACE_CPUFLAG_CLEAR(CPU_DTRACE_NOFAULT);
+
+		if (DTRACE_CPUFLAG_ISSET(CPU_DTRACE_FAULT))
+			break;
 
 		if (addr >= tos && addr <= bos) {
 			/* stack address - may need it for the fpstack. */
-- 
2.50.1