Re: [PATCH v10 05/18] mm: mark vmas detached upon exit
From: Liam R. Howlett
Date: Fri Feb 21 2025 - 11:24:59 EST
* Suren Baghdasaryan <surenb@xxxxxxxxxx> [250213 17:47]:
> 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@xxxxxxxxxx>
> Reviewed-by: Vlastimil Babka <vbabka@xxxxxxx>
> Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> ---
> Changes since v9 [1]:
> - Add Reviewed-by, per Lorenzo Stoakes
>
> [1] https://lore.kernel.org/all/20250111042604.3230628-6-surenb@xxxxxxxxxx/
>
> mm/vma.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/mm/vma.c b/mm/vma.c
> index f72b73f57451..a16a83d0253f 100644
> --- a/mm/vma.c
> +++ b/mm/vma.c
> @@ -427,10 +427,12 @@ 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);
> + }
> }
>
> /*
> --
> 2.48.1.601.g30ceb7b040-goog
>