[Qemu-devel] [PATCH v3] linux-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag()

[chengang]

From: Chen Gang <address@hidden>

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

Signed-off-by: Chen Gang <address@hidden>
---
 linux-user/mmap.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 7b459d5..c6c478e 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;
 }
-- 
1.7.3.4