From 3d4339609875e273966ffab5b76526a0bf07963d Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <ian@gcc.gnu.org>
Date: Tue, 1 Nov 2011 04:55:15 +0000
Subject: [PATCH] runtime: Correct test of mmap return value.

From-SVN: r180731
---
 libgo/runtime/mem.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libgo/runtime/mem.c b/libgo/runtime/mem.c
index 4267c55fb47c..4e1103e130a5 100644
--- a/libgo/runtime/mem.c
+++ b/libgo/runtime/mem.c
@@ -85,6 +85,7 @@ void*
 runtime_SysReserve(void *v, uintptr n)
 {
 	int fd = -1;
+	void *p;
 
 	// On 64-bit, people with ulimit -v set complain if we reserve too
 	// much address space.  Instead, assume that the reservation is okay
@@ -103,7 +104,11 @@ runtime_SysReserve(void *v, uintptr n)
 	fd = dev_zero;
 #endif
 
-	return runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, fd, 0);
+	p = runtime_mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, fd, 0);
+	if((uintptr)p < 4096 || -(uintptr)p < 4096) {
+		return nil;
+	}
+	return p;
 }
 
 void