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[PULL,11/17] linux-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag()

Message ID e6deac9cf99e013a3e253aff2332836c86d8a52c.1452521686.git.riku.voipio@linaro.org
State New
Headers show

Commit Message

Riku Voipio Jan. 11, 2016, 2:16 p.m. UTC 
From: Chen Gang <chengang@emindsoft.com.cn>

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(-)
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Patch

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;
 }