Re: [PATCH v7 05/17] mm: mark vmas detached upon exit

Vlastimil Babka
2025-01-07T17:08:31Z

On 12/26/24 18:06, Suren Baghdasaryan wrote:
> When exit_mmap() removes vmas belonging to an exiting task, it does not
> mark them as detached since they can't be reached by other tasks and they
> will be freed shortly. Once we introduce vma reuse, all vmas will have to
> be in detached state before they are freed to ensure vma when reused is
> in a consistent state. Add missing vma_mark_detached() before freeing the
> vma.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

> ---
> mm/vma.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/vma.c b/mm/vma.c
> index ce113dd8c471..4a3deb6f9662 100644
> --- a/mm/vma.c
> +++ b/mm/vma.c
> @@ -413,9 +413,10 @@ void remove_vma(struct vm_area_struct *vma, bool unreachable)
> if (vma->vm_file)
> fput(vma->vm_file);
> mpol_put(vma_policy(vma));
> - if (unreachable)
> + if (unreachable) {
> + vma_mark_detached(vma);
> __vm_area_free(vma);
> - else
> + } else
> vm_area_free(vma);

Nit: per style this should be { } too now.

> }
>