diff mbox

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

Message ID 1451437854-3708-1-git-send-email-chengang@emindsoft.com.cn
State New
Headers show

Commit Message

Chen Gang Dec. 30, 2015, 1:10 a.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>
---
 linux-user/mmap.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

Comments

Laurent Vivier Dec. 30, 2015, 1:14 a.m. UTC | #1 
Le 30/12/2015 02:10, chengang@emindsoft.com.cn a écrit :
> 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>
> ---
>  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;
>  }
> 

Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Chen Gang Dec. 31, 2015, 1:10 p.m. UTC | #2 
On 12/30/15 09:14, Laurent Vivier wrote:
> 
> Le 30/12/2015 02:10, chengang@emindsoft.com.cn a écrit :
>> 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>
>> ---
>>  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;
>>  }
>>
> 
> Reviewed-by: Laurent Vivier <laurent@vivier.eu>
> 

Thank you for your work.


Happy New Year!  :-)
diff mbox

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;
 }