From b1b706453f3761d4aa927c6f9b124d74abb8670a Mon Sep 17 00:00:00 2001
From: NAKAMURA Gou <go.nakamura.yw@hitachi-solutions.com>
Date: Wed, 16 Sep 2015 13:14:18 +0900
Subject: [PATCH] vsyscall: send SIGSEGV to the caller if syscall fails

On CentOS 7 (RHEL 7?), "errno" isn't set when vsyscall_gettimeofday
fails. So, in such case, vsyscall_gettimeofday send SIGSEGV to the
caller to report failure of gettimeofday operation.
---
 arch/x86/kernel/vsyscall.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kernel/vsyscall.c b/arch/x86/kernel/vsyscall.c
index c4e3dd1e..40cfe21d 100644
--- a/arch/x86/kernel/vsyscall.c
+++ b/arch/x86/kernel/vsyscall.c
@@ -30,6 +30,9 @@ int vsyscall_gettimeofday(void *tv, void *tz)
 			: "a" (__NR_gettimeofday), "D" (tv), "S" (tz)
 			: "%rcx", "%r11", "memory");
 
+	if (error) {
+		*(int *)0 = 0;	/* i.e. raise(SIGSEGV) */
+	}
 	return error;
 }