From e6deac9cf99e013a3e253aff2332836c86d8a52c Mon Sep 17 00:00:00 2001
From: Chen Gang <chengang@emindsoft.com.cn>
Date: Wed, 30 Dec 2015 09:10:54 +0800
Subject: [PATCH] linux-user/mmap.c: Always zero MAP_ANONYMOUS memory in
 mmap_frag()

When mapping MAP_ANONYMOUS memory fragments, still need notice about to
set it zero, or it will cause issues.

Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
---
 linux-user/mmap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 7b459d5100..c6c478e552 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -186,10 +186,12 @@ static int mmap_frag(abi_ulong real_start,
         if (prot_new != (prot1 | PROT_WRITE))
             mprotect(host_start, qemu_host_page_size, prot_new);
     } else {
-        /* just update the protection */
         if (prot_new != prot1) {
             mprotect(host_start, qemu_host_page_size, prot_new);
         }
+        if (prot_new & PROT_WRITE) {
+            memset(g2h(start), 0, end - start);
+        }
     }
     return 0;
 }