From deb521c44fa529b24cc78a64702757a683f82487 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Fri, 19 Oct 2012 13:37:57 -0700 Subject: [PATCH] remap_file_pages: correctly handle the case of a NULL vm_ops pointer In commit 0b173bc4daa8 ("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 Cc: Konstantin Khlebnikov Cc: Andrew Morton Signed-off-by: Linus Torvalds --- mm/fremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/fremap.c b/mm/fremap.c index 3899a86851c..a0aaf0e5680 100644 --- 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)