Re: [PATCH 3/5] mm/vmalloc: Initialize VA's list node after unlink

Baoquan He
2022-06-08T05:53:46Z

On 06/07/22 at 11:34am, Uladzislau Rezki (Sony) wrote:
> A vmap_area can travel between different places. For example
> attached/detached to/from different rb-trees. In order to
> prevent fancy bugs, initialize a VA's list node after it is
> removed from the list, so it pairs with VA's rb_node which
> is also initialized.
>
> There is no functional change as a result of this patch.
>
> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
> ---
> mm/vmalloc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 745e89eb6ca1..82771e555273 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -978,7 +978,7 @@ __unlink_va(struct vmap_area *va, struct rb_root *root, bool augment)
> else
> rb_erase(&va->rb_node, root);
>
> - list_del(&va->list);
> + list_del_init(&va->list);

Don't object this change, while list_del poison members, which is also
not bad?

static inline void list_del(struct list_head *entry)
{
__list_del_entry(entry);
entry->next = LIST_POISON1;
entry->prev = LIST_POISON2;
}

> RB_CLEAR_NODE(&va->rb_node);
> }
>
> --
> 2.30.2
>
>