On Mon, 14 Aug 2023 16:54:01 +0200 Jann Horn <jannh@xxxxxxxxxx> wrote:
> > @@ -403,6 +403,8 @@ static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma)
> >
> > vma_iter_store(&vmi, vma);
> >
> > + vma_start_write(vma);
> > +
> > if (vma->vm_file) {
> > mapping = vma->vm_file->f_mapping;
> > i_mmap_lock_write(mapping);
>
> The "vma_start_write()" has to be ordered before the
> "vma_iter_store(&vmi, vma)".
Thanks. This?
--- a/mm/mmap.c~mm-always-lock-new-vma-before-inserting-into-vma-tree-fix
+++ a/mm/mmap.c
@@ -401,10 +401,10 @@ static int vma_link(struct mm_struct *mm
if (vma_iter_prealloc(&vmi, vma))
return -ENOMEM;
- vma_iter_store(&vmi, vma);
-
vma_start_write(vma);
+ vma_iter_store(&vmi, vma);
+
if (vma->vm_file) {
mapping = vma->vm_file->f_mapping;
i_mmap_lock_write(mapping);
_
