diff mbox series

[v2,1/9] bsd-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag()

Message ID 20210922045636.25206-2-imp@bsdimp.com (mailing list archive)
State New, archived
Headers show
Series bsd-user mmap fixes | expand

Commit Message

Warner Losh Sept. 22, 2021, 4:56 a.m. UTC 
From: Mikaël Urankar <mikael.urankar@gmail.com>

Similar to the equivalent linux-user commit e6deac9cf99

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

Signed-off-by: Mikaël Urankar <mikael.urankar@gmail.com>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/mmap.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Richard Henderson Sept. 23, 2021, 5:35 p.m. UTC | #1 
On 9/21/21 9:56 PM, Warner Losh wrote:
> From: Mikaël Urankar<mikael.urankar@gmail.com>
> 
> Similar to the equivalent linux-user commit e6deac9cf99
> 
> When mapping MAP_ANONYMOUS memory fragments, still need notice about to
> set it zero, or it will cause issues.
> 
> Signed-off-by: Mikaël Urankar<mikael.urankar@gmail.com>
> Signed-off-by: Warner Losh<imp@bsdimp.com>
> ---
>   bsd-user/mmap.c | 4 +++-
>   1 file changed, 3 insertions(+), 1 deletion(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~
diff mbox series

Patch

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index b40ab9045f..fc3c1480f5 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -180,10 +180,12 @@  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_untagged(start), 0, end - start);
+        }
     }
     return 0;
 }