From e4cc9c81e2305aabfa9a0e46e17d3895a10ba3d8 Mon Sep 17 00:00:00 2001 From: zhong jiang Date: Mon, 18 Nov 2019 11:26:08 +0800 Subject: [PATCH] memfd: Use radix_tree_deref_slot_protected to avoid the warning. 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@vger.kernel.org Fixes: 99b45e7a1ba1 ("memfd: Fix locking when tagging pins") Signed-off-by: zhong jiang Reviewed-by: Matthew Wilcox (Oracle) Signed-off-by: Greg Kroah-Hartman --- 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); -- GitLab