On Fri, 17 Feb 2017 16:52:41 +0100 Andrea Arcangeli <aarcange@xxxxxxxxxx> wrote:
> Everything else is identical which is great. Mike Rapoport could you
> verify the below hunk is missing in mm?
>
> Once it'll all be merged upstream then there will be less merge crunch
> as we've been working somewhat in parallel on the same files, so this
> is resulting in more merge rejects than ideal :).
>
> diff --git a/../mm/mm/userfaultfd.c b/mm/userfaultfd.c
> index 830bed7..3ec9aad 100644
> --- a/../mm/mm/userfaultfd.c
> +++ b/mm/userfaultfd.c
> @@ -199,6 +201,12 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
> dst_vma = find_vma(dst_mm, dst_start);
> if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
> goto out_unlock;
> + /*
> + * Only allow __mcopy_atomic_hugetlb on userfaultfd
> + * registered ranges.
> + */
> + if (!dst_vma->vm_userfaultfd_ctx.ctx)
> + goto out_unlock;
>
> if (dst_start < dst_vma->vm_start ||
> dst_start + len > dst_vma->vm_end)
> @@ -214,16 +224,10 @@ static __always_inline ssize_t __mcopy_atomic_hugetlb(struct mm_struct *dst_mm,
> goto out_unlock;
>
> /*
> - * Only allow __mcopy_atomic_hugetlb on userfaultfd registered ranges.
> - */
> - if (!dst_vma->vm_userfaultfd_ctx.ctx)
> - goto out_unlock;
> -
> - /*
> * If not shared, ensure the dst_vma has a anon_vma.
> */
I merged this up and a small issue remains:
: /*
: * Validate alignment based on huge page size
: */
: err = -EINVAL;
: if (dst_start & (vma_hpagesize - 1) || len & (vma_hpagesize - 1))
: goto out_unlock;
:
:retry:
: /*
: * On routine entry dst_vma is set. If we had to drop mmap_sem and
: * retry, dst_vma will be set to NULL and we must lookup again.
: */
: if (!dst_vma) {
: err = -ENOENT;
: dst_vma = find_vma(dst_mm, dst_start);
: if (!dst_vma || !is_vm_hugetlb_page(dst_vma))
: goto out_unlock;
: /*
: * Only allow __mcopy_atomic_hugetlb on userfaultfd
: * registered ranges.
: */
: if (!dst_vma->vm_userfaultfd_ctx.ctx)
: goto out_unlock;
:
: if (dst_start < dst_vma->vm_start ||
: dst_start + len > dst_vma->vm_end)
: goto out_unlock;
:
: err = -EINVAL;
: if (vma_hpagesize != vma_kernel_pagesize(dst_vma))
: goto out_unlock;
: }
:
: if (WARN_ON(dst_addr & (vma_hpagesize - 1) ||
: (len - copied) & (vma_hpagesize - 1)))
: goto out_unlock;
The value of `err' here is EINVAL. That sems appropriate, but it only
happens by sheer luck.
: /*
: * If not shared, ensure the dst_vma has a anon_vma.
: */
: err = -ENOMEM;
: if (!(dst_vma->vm_flags & VM_SHARED)) {
: if (unlikely(anon_vma_prepare(dst_vma)))
: goto out_unlock;
: }
So...
--- a/mm/userfaultfd.c~userfaultfd-mcopy_atomic-return-enoent-when-no-compatible-vma-found-fix-2-fix
+++ a/mm/userfaultfd.c
@@ -215,6 +215,7 @@ retry:
goto out_unlock;
}
+ err = -EINVAL;
if (WARN_ON(dst_addr & (vma_hpagesize - 1) ||
(len - copied) & (vma_hpagesize - 1)))
goto out_unlock;
_
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