remap_file_pages: correctly handle the case of a NULL vm_ops pointer

In commit 0b173bc ("mm: kill vma flag VM_CAN_NONLINEAR") we replaced the VM_CAN_NONLINEAR test with checking whether the mapping has a '->remap_pages()' vm operation, but there is no guarantee that there it even has a vm_ops pointer at all. Add the appropriate test for NULL vm_ops. Reported-by: Sasha Levin <[email protected]> Cc: Konstantin Khlebnikov <[email protected]> Cc: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
baoh · Oct 19, 2012 · deb521c · deb521c
1 parent 17dbe27
commit deb521c
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/mm/fremap.c b/mm/fremap.c
@@ -169,7 +169,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 	if (vma->vm_private_data && !(vma->vm_flags & VM_NONLINEAR))
 		goto out;
 
-	if (!vma->vm_ops->remap_pages)
+	if (!vma->vm_ops || !vma->vm_ops->remap_pages)
 		goto out;
 
 	if (start < vma->vm_start || start + size > vma->vm_end)