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>
---
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
