On Thu, Jul 06, 2023 at 10:28:48AM +0000, Alan Huang wrote:
> When the objects managed by rculist_nulls are allocated with
> SLAB_TYPESAFE_BY_RCU, readers may still hold references to this
> object that is being added, which means the modification of ->next
> is visible to readers. So, this patch uses WRITE_ONCE() for assignments
> to ->next.
>
> Signed-off-by: Alan Huang <mmpgouride@xxxxxxxxx>
Very good, queued for the v6.6 merge window, thank you!
Thanx, Paul
> ---
> include/linux/rculist_nulls.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h
> index ba4c00dd8005..89186c499dd4 100644
> --- a/include/linux/rculist_nulls.h
> +++ b/include/linux/rculist_nulls.h
> @@ -101,7 +101,7 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n,
> {
> struct hlist_nulls_node *first = h->first;
>
> - n->next = first;
> + WRITE_ONCE(n->next, first);
> WRITE_ONCE(n->pprev, &h->first);
> rcu_assign_pointer(hlist_nulls_first_rcu(h), n);
> if (!is_a_nulls(first))
> @@ -137,7 +137,7 @@ static inline void hlist_nulls_add_tail_rcu(struct hlist_nulls_node *n,
> last = i;
>
> if (last) {
> - n->next = last->next;
> + WRITE_ONCE(n->next, last->next);
> n->pprev = &last->next;
> rcu_assign_pointer(hlist_nulls_next_rcu(last), n);
> } else {
> --
> 2.34.1
>
