fix mprotect vma_wants_writenotify prot

Fix mprotect bug in recent commit 3ed75eb8f1cd89565966599c4f77d2edb086d5b0
(setup vma->vm_page_prot by vm_get_page_prot()): the vma_wants_writenotify
case was setting the same prot as when not.

Nothing wrong with the use of protection_map[] in mmap_region(),
but use vm_get_page_prot() there too in the same ~VM_SHARED way.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Coly Li <coyli@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 55227845abbe..4de546899dc1 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -194,7 +194,7 @@ success:
         vma->vm_flags = newflags;
         vma->vm_page_prot = vm_get_page_prot(newflags);
         if (vma_wants_writenotify(vma)) {
-                vma->vm_page_prot = vm_get_page_prot(newflags);
+                vma->vm_page_prot = vm_get_page_prot(newflags & ~VM_SHARED);
                 dirty_accountable = 1;
         }