fix the arch checks in MREMAP_FIXED case

Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 17 insertions, 2 deletions

diff --git a/mm/mremap.c b/mm/mremap.c
index 9d0753983dcb..84efffb2d2c4 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -325,6 +325,7 @@ static unsigned long mremap_to(unsigned long addr,
         struct vm_area_struct *vma;
         unsigned long ret = -EINVAL;
         unsigned long charged = 0;
+        unsigned long map_flags;
 
         if (new_addr & ~PAGE_MASK)
                 goto out;
@@ -362,9 +363,23 @@ static unsigned long mremap_to(unsigned long addr,
                 goto out;
         }
 
-        ret = move_vma(vma, addr, old_len, new_len, new_addr);
+        map_flags = MAP_FIXED;
+        if (vma->vm_flags & VM_MAYSHARE)
+                map_flags |= MAP_SHARED;
+        ret = arch_mmap_check(new_addr, new_len, map_flags);
+        if (ret)
+                goto out1;
+        ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
+                                ((addr - vma->vm_start) >> PAGE_SHIFT),
+                                map_flags);
         if (ret & ~PAGE_MASK)
-                vm_unacct_memory(charged);
+                goto out1;
+
+        ret = move_vma(vma, addr, old_len, new_len, new_addr);
+        if (!(ret & ~PAGE_MASK))
+                goto out;
+out1:
+        vm_unacct_memory(charged);
 
 out:
         return ret;