commit 948516a3fac0bdd47eb127fe1a86148ed86d5c65
author Mikaël Urankar <mikael.urankar@gmail.com> Sat Jul 08 13:13:31 2017 +0200
committer Warner Losh <imp@bsdimp.com> Sun Oct 17 16:55:52 2021 -0600
tree 219564265174a41a9b29af0f3db659d540849891
parent c148a0572130ff485cd2249fbdd1a3260d5e10a4

bsd-user/mmap.c: Always zero MAP_ANONYMOUS memory in mmap_frag()

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>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Kyle Evans <kevans@FreeBSD.org>

bsd-user/mmap.c

diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index b40ab90..fc3c148 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -180,10 +180,12 @@
         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;
 }