The commit 99b45e7a1ba1 ("memfd: Fix locking when tagging pins")
introduces the following warning messages.
*WARNING: suspicious RCU usage in memfd_wait_for_pins*
It is because we still use radix_tree_deref_slot without read_rcu_lock.
We should use radix_tree_deref_slot_protected instead in the case.
Cc: stable@xxxxxxxxxxxxxxx
Fixes: 99b45e7a1ba1 ("memfd: Fix locking when tagging pins")
Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
---
mm/memfd.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memfd.c b/mm/memfd.c
index 5859705dafe1..9e68a4320a0e 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -41,7 +41,7 @@ static void memfd_tag_pins(struct address_space *mapping)
xa_lock_irq(&mapping->i_pages);
radix_tree_for_each_slot(slot, &mapping->i_pages, &iter, start) {
- page = radix_tree_deref_slot(slot);
+ page = radix_tree_deref_slot_protected(slot, &mapping->i_pages.xa_lock);
if (!page || radix_tree_exception(page)) {
if (radix_tree_deref_retry(page)) {
slot = radix_tree_iter_retry(&iter);
--
2.20.1
