From 988f701a805bf980e70a557894d26564e10fc1a6 Mon Sep 17 00:00:00 2001 From: zhong jiang Date: Mon, 18 Nov 2019 11:26:07 +0800 Subject: memfd: Use radix_tree_deref_slot_protected to avoid the warning. The commit 391d4ee568b5 ("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: 391d4ee568b5 ("memfd: Fix locking when tagging pins") Signed-off-by: zhong jiang Reviewed-by: Matthew Wilcox (Oracle) Signed-off-by: Greg Kroah-Hartman --- mm/shmem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/shmem.c b/mm/shmem.c index 5b2cc9f9b1f1..e55aa460a2c0 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2664,7 +2664,7 @@ static void shmem_tag_pins(struct address_space *mapping) spin_lock_irq(&mapping->tree_lock); radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { - page = radix_tree_deref_slot(slot); + page = radix_tree_deref_slot_protected(slot, &mapping->tree_lock); if (!page || radix_tree_exception(page)) { if (radix_tree_deref_retry(page)) { slot = radix_tree_iter_retry(&iter); -- cgit v1.2.3