[PATCH 1/2] mremap: don't allow VM_MIXEDMAP vma expanding

[Shaohua Li <shli@fb.com>]

Drivers using vm_insert_page() will set VM_MIXEDMAP, but their .fault
handler are likely not prepared to handle expansion.

Cc: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Shaohua Li <shli@fb.com>
---
 mm/mremap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index 17fa018..3b886dc 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -354,7 +354,7 @@ static struct vm_area_struct *vma_to_resize(unsigned long addr,
 	if (new_len > old_len) {
 		unsigned long pgoff;
 
-		if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP))
+		if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP))
 			goto Efault;
 		pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
 		pgoff += vma->vm_pgoff;
-- 
1.8.1

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