On Tue, Sep 27, 2016 at 06:08:07PM +0200, Jan Kara wrote:
> struct vm_fault has already pgoff entry. Use it instead of passing pgoff
> as a separate argument and then assigning it later.
>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> mm/memory.c | 35 ++++++++++++++++++-----------------
> 1 file changed, 18 insertions(+), 17 deletions(-)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index 447a1ef4a9e3..4c2ec9a9d8af 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -2275,7 +2275,7 @@ static int wp_pfn_shared(struct vm_fault *vmf, pte_t orig_pte)
> if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) {
> struct vm_fault vmf2 = {
> .page = NULL,
> - .pgoff = linear_page_index(vma, vmf->address),
> + .pgoff = vmf->pgoff,
I think there is one path where vmf->pgoff isn't set here. Here's the path:
__collapse_huge_page_swapin()
do_swap_page()
do_wp_page()
wp_pfn_shared()
We then use an uninitialized vmf->pgoff to set up vmf2->pgoff, which we pass
to vm_ops->pfn_mkwrite().
I think all we need to do to fix this is initialize .pgoff in
__collapse_huge_page_swapin(). With this one change:
Reviewed-by: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
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