On Mon, Feb 27, 2023 at 09:36:16AM -0800, Suren Baghdasaryan wrote: > Write-lock VMA as locked before copying it and when copy_vma produces > a new VMA. > > Signed-off-by: Suren Baghdasaryan <sur...@google.com> > Reviewed-by: Laurent Dufour <laurent.duf...@fr.ibm.com> > --- > mm/mmap.c | 1 + > mm/mremap.c | 1 + > 2 files changed, 2 insertions(+) > > diff --git a/mm/mmap.c b/mm/mmap.c > index e73fbb84ce12..1f42b9a52b9b 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -3189,6 +3189,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct > **vmap, > get_file(new_vma->vm_file); > if (new_vma->vm_ops && new_vma->vm_ops->open) > new_vma->vm_ops->open(new_vma); > + vma_start_write(new_vma);
Oh, it's to prevent handling page faults during move_page_tables(). > if (vma_link(mm, new_vma)) > goto out_vma_link; > *need_rmap_locks = false; > diff --git a/mm/mremap.c b/mm/mremap.c > index 1ddf7beb62e9..327c38eb132e 100644 > --- a/mm/mremap.c > +++ b/mm/mremap.c > @@ -623,6 +623,7 @@ static unsigned long move_vma(struct vm_area_struct *vma, > return -ENOMEM; > } > > + vma_start_write(vma); > new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT); > new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff, > &need_rmap_locks); > -- > 2.39.2.722.g9855ee24e9-goog Looks good to me. Reviewed-by: Hyeonggon Yoo <42.hye...@gmail.com> > >
